Stanford Releases CFD Tools as Open Source

Aircraft solution computed using SU2. Image from Stanford's Aerospace Design Lab.

The Aerospace Design Lab at Stanford University announced the open-source release of its C++ software tools for solving PDEs. The software suite is called SU² meaning Stanford University Unstructured and while it has been designed primarily for CFD it can be used for other applications such as electromagnetics.  The software computes the flow but also computes adjoint solutions, does gradient based optimization, and deforms the mesh.

One week after Stanford’s announcement, the code (which supports Linux and Mac OS X) has been downloaded over 300 times.

• SU² website
• Stanford’s Aerospace Design Lab

EnSight 10 to be Integrated Into FLOW-3D

Flow Science and CEI have partnered to integrate CEI’s EnSight 10 CFD postprocessing software into Flow Science’s FLOW-3D CFD solver. The combination will give FLOW-3D users a client-server architecture for use in postprocessing, all of EnSight’s advanced postprocessing capabilities, and Python-based customization.

A beta version of the integrated products is expected this fall with a production release next year. A “sneak peak” will be available at the FLOW-3D European Users Conference this summer.

• CEI’s announcement

Sunglass.io Promises to Democratize Design Computation

CAD model demo at Sunglass.io

Sunglass.io is a new startup that has created a web-based 3D application called Stage for sharing and collaborating on 3D models. In the future they plan to release something called Sim which will use their servers as the backend for heavier computations such as CFD. [At this time, Sunglass.io seems like something to keep an eye on.]

• Sunglass.io on SolidSmack
• Sunglass.io

GeekoCFD Bundles Open Source CFD Tools

GeekoCFD is a collection of CFD tools built on OpenSUSE 64-bit Linux provided with the intent of “easy and immediate” access to open-source CFD tools including gmsh, OpenFOAM, Paraview, Blender, and more.

• GeekoCFD

This, That, and The Other

• Enclosure heaters designed with CFD
• CFD modeling of the aortic valve
• Simulating a fire sprinkler with SolidWorks Flow Simulation
• CONVERGE CFD is mentioned in this issue of SAE’s Powertrain & Energy
• A video explanation of why air moving faster over a wing’s upper surface is not the source of lift
• Building better reactors with CFD from CD-adapco

“Why CAD Will Wither on Apple”

CAD expert Ralph Grabowski posted the article Why CAD Will Wither on Apple on the WorldCAD Access blog. In his post he says that Apple will never be well suited for CAD because Apple doesn’t doesn’t understand the special needs of that industry.

I tend to think of CAD and meshing software as being very similar. Certainly meshing software lacks the breadth of CAD’s design tools. But meshing software has to carry around the geometry and create a mesh on it too.  While the Mac hasn’t vaulted to the top of our supported platforms list (it’s third behind Windows and Linux) neither we nor our Mac customers have found anything that prevents it from being a suitable platform.

Ralph says that CAD apps need lots of RAM, a full OpenGL implementation, and intimate access to the graphics chip among other things.

What do you think about CAD, CFD or meshing software on Mac? If you’re curious, why not give Pointwise for Mac OS X a try?

Stanford Released SU2 Version 1.1

SU2 Workflow. Image courtesy of Stanford Univ.

Stanford University released Version 1.1 of their SU2 (Stanford University Unstructured) open-source CFD code. New in this latest release are Windows executables, better parallelization, a Pointwise plugin for native export of SU2′s files, an SST turbulence model, periodic boundary conditions, and more.

• Stanford’s announcement

[Yes, I realize that Stanford writes SU2 as SU² with the superscript. But I'm too lazy to do all that formatting.]

CD-adapco Released STAR-CD v4.18

STAR-CD v4.18 and es-ICE for for IC simulation. Image from CD-adapco.

CD-adapco released STAR-CD version 4.18 with a variety of improvements in preprocessing for in-cylinder flows including automatic 2D templates, a single command for mesh coarsening and refining, and spray adaption. Several enhancements to chemistry in the solver are also included.

• CD-adapco’s announcement

News in Brief

• Autodesk has launched an online wiki for their Simulation CFD product. The wiki includes articles, videos, and other resources.
• The folks at the Particle in Cell blog have gone one step beyond their SVG/Javascript demo of editing a B-Spline curve and now have developed an SVG/Javascript app for elliptic grid generation.
• NASA launched their new Technology Transfer Portal for the purpose of streamlining and increasing the rate of transfer of NASA’s intellectual property to the private sector for commercialization. [Oddly, the advanced search tool for software returned zero results for "CFD" but when searching for "mesh" I got one hit - the CART3D inviscid CFD code.]
• ERCOFTAC announced a 2-day workshop on CFD for Dispersed Multi-Phase Flows to be held 18-19 July 2012 in Graz, Austria.
• Turbulence modelling expert Dr. Florian Menter will conduct three seminars on Turbulence Modelling for Industrial Applications in Australia during August.
• Applications of CFD that get widely publicized include Formula 1 cars, data centers, and racing bicycles.
• blueCAPE launched blueCFD, a Windows port of OpenFOAM.
• Acer and NVIDIA demonstrate a “supercomputer in a box” for CFD. [Honestly, I couldn't figure out exactly what the point of the full article is.]
• SIGGRAPH is seeking computer graphics professionals to mentor select high school students who’ll be attending the conference.
• CD-adapco and Red Cedar Technology have partnered on add-ons for STAR-CCM+ for process automation and optimization.

Exa’s IPO

Exa Corporation, makers of the Lattice Boltzmann-based PowerFLOW suite of CFD software, went public this week on the NASDAQ trading under the symbol EXA. CAE blogger Monica Schnitger has been tracking the IPO and revealed some interesting nuggets.

• Exa’s top 10 customers account for 69% of their revenue.
• Revenue in FY 2012 was up 21%.
• In FY 2013 Q1, software revenue increased 9% with 30% of the increase coming from new customers (i.e. new new sales) and 70% coming from additions by existing customers (i.e. new sales).

The initial plan for the IPO was to offer over 6 million shares for between $11-$13 but in the end the offer price was $10. After falling on the first day of trading yesterday, Exa’s stock price has risen to $10.10 as of the time of this writing.

Exa is believed to be the only all-CFD company that’s publicly traded. With annual revenue of $46,000,000 they are the 3rd largest provider of CFD solutions.

• Schnitger’s blog post

Jobs

• Tecplot is seeking applicants for the following positions: Director of Customer Development, Network Administration Supervisor, Software Test Engineer, UX Designer, and Software Development Engineer.
• Pointwise is seeking applicants for the following positions: Software Development Engineer, Technical Support Engineer.

Going 800 mph With CFD

CFD has for a long time been applied to aircraft and automobiles. But what about an aircraft that has been converted into an automobile?

• Start with an F-104 fighter aircraft.
• Remove the wings.
• Add wheels.
• Attempt to drive 800 mph and break the land speed record.

CFD solution for NAE’s land speed record attempting car.

In what [IMO] should be a very interesting webinar, Pointwise and CEI Software team up with North American Eagle to share how they apply CFD to the design of the car for their attempt at breaking the land speed record. The webinar will be on 7 November 2012 at 11:00 a.m. CST.

• Pointwise’s webinar page
• North American Eagle’s website

Simulation Driven Design – Who Has to Enable the Change?

That’s the title of a video debate on Engineering.com’s Tech4PD channel about how we go about achieving what everyone agrees we should be doing – applying simulation early in the design process. There is general agreement that simulation should be done early in the design process to best influence “lines freeze” and other decisions as opposed to waiting until later in the design process when the design is too rigid to be influenced significantly and instead simulation becomes an exercise in verification and validation. (Or worse yet, simulation is used to perform post-mortem analysis.)

The debaters, Tech-Clarity’s Jim Brown and Lifecycle Insights’ Chad Jackson, agree that the pertinent issues are understanding of engineering physics, understanding of the simulation method, and fluency with both the simulation and CAD software.

Opinions differ, however, on whether A) simulation tools move into the hands of engineers or B) whether analysts get involved further upstream in the design process. Here’s my take on the issues cited above with respect to this topic.

• Engineering physics – If you take the position that engineers (i.e. people designing things in CAD software) are “jack’s of all trades, master of none” whereas analysts are narrowly proficient in one area of expertise (e.g. fluid dynamics) you’d reach the conclusion that the analysts ought to be the ones performing simulation (i.e. option B above). However, I’d like to believe that the engineers designing things have been sufficiently schooled by universities in the fundamentals that they can tell whether the simulation software is giving them realistic results (which is what we’re mostly worried about, I think).
• Simulation methodology – On the other hand, I don’t think an engineer needs to understand a simulation methodology other than its range of applicability. And I’m hoping that someone at the company has already validated the simulation tools for the particular types of configurations to be studied. The nuts and bolts of the methodology under the hood in the analysis software are truly best left to the dedicated analyst (option B). In fact, you can make the argument that the analysts should be crafting tools to ensure they can be applied by non-experts.
• Fluency with the software – This is a toss up. There’s an implied belief that simulation software is much harder to use than CAD software. Modern CAD software is pretty darn complex and knowing how to get it to do what you need takes a degree of skill.

Another component of the argument for option A was that analysts are too busy doing other analyses (presumably V&V or post-mortems) to also ask them to do work in preliminary design. However, the fundamental premise of the debate is that by doing more analysis and simulation early in the process, you’ll decrease the need for doing V&V. Therefore, this is another win for option B.

There’s one flaw in this debate however. It assumes an organization large enough to have a team of engineers designing things and across the wall another team of analysts who are analyzing things. Often we are talking about organizations where only a handful of people are responsible for both functions.

As you can surmise, my position on the issue is that analysts should be more involved in the preliminary design process (option B). If you watch the 10 minute video you too can vote online and see how everyone else feels. (I won’t spoil the surprise but almost 70% of the votes as of this morning were going to one of the two options – it’s not very close.)

• Simulation Driven Design video debate at Engineering.com

[Sorry for rambling. This probably should've been a blog post unto itself.]

Wyoming Grad Student Wins Supercomputing Trip

Jared Baker and his winning poster. Image from U. of Wyoming.

University of Wyoming graduate student Jared Baker won an all expenses paid trip to Supercomputing 12 for his poster presentation on Computational Investigation of Spoiler Attachment on Wind Turbine Blades.  His 3D CFD work indicated that adding a spoiler near the root section of a wind turbine blade can increase efficiency by 2-5%.

If you see Jared at Supercomputing be sure to congratulate him on his work. If you won’t be at the conference, you can hear Jared describe his work by playing the audio file on UW’s website.

• University of Wyoming’s announcement
• UW’s Dept. of Mechanical Engineering website
• SC12 conference website

News in Brief

• Active flow control for eliminating a submarine’s wake. [Although CFD is not mentioned in this article, the application sounds perfect for it.]
• ERCOFTAC is hosting a short course on computational aeroacoustics to be held 30-31 October 2012 in Munich.
• The 2nd Australian OpenFOAM User Group Meeting will be held on 26 November 2012 in Melbourne, Australia.
• Intelligent Light, makers of the FieldView CFD postprocessing software, have created a Japanese language version of their website.
• The keynote speaker for the CD-adapco STAR Japanese Conference will be Vince Johnson from Tesla Motors.
• ThermoAnalytics released a new version of their CFD Manager for use in transient thermal simulations.
• Stanford University will introduce version 2.0 of their open source CFD code, SU2, at the AIAA Aerospace Sciences meeting on 8 January 2013.
• Rolls Royce North America has an opening for a CFD Methods Specialist.
• A preliminary announcement reveals that the next user meeting for the Code_Saturne open source CFD code will be held in the spring of 2013.

Furniture for Mesh Generators

From J1studio comes the modular T.shelf, a shelving system only an unstructured mesh generator could love. [Although I'll quibble with their statement that the triangle is "the strongest geometric shape." Isn't that the circle/sphere?]

Software Releases

• Stanford will release v2.0 of their SU2 open source CFD code on 8 January. Two other events are planned in conjunction with that release.
  • A presentation at the AIAA Aerospace Sciences Meeting on 7 January at 4pm.
  • A workshop on 15 January.
• Siemens PLM Software announced the release of Parasolid V25.0, the latest version of their solid modeling kernel. Technical details of the curve, surface, and optimization improvements can be found at their Introducing V25.0 page.
• Exa released PowerDELTA 1.7 for mesh preparation. [I had always thought the beauty of Exa's CFD software was that it didn't need a mesh.]
• 3-D modeler Rhino 5 was released including supposedly 3,500 enhancements.
• Beta CAE released ANSA v13.2.4.
• CEI released TSV-Pre/Post Ver. 6 for FEA pre- and postprocessing.

SU2 computed streaklines behind a cylinder at Re=100.

CAD Interoperability Today

That’s the title of an excellent summary article by Design World’s Evan Yares about the current state of the art when it comes to exchanging CAD data from application to application. And because CAD data is the starting point for meshing and meshing is the starting point for CFD, it’s important for us to understand what the issues are.

And there are plenty of issues. While interoperability “is getting better all the time,” Yares writes “interoperability problems are par for the course” and will continue to be so “for the foreseable future.” This is another verse of a song I know very well – mesh generation also sucks but is getting better all the time.

You might want to read Yares’ article first: CAD Interoperability Today. [Actually, you should read it. Do so now.]

Be Tolerant of Tolerances

Yares offers a point-counterpoint argument about whether tolerancing (setting a small numerical value below which geometries are considered identical or adjacent) is the key culprit in the lack of CAD interoperability because different systems (e.g. the CAD system and the mesh generator) use different tolerances and/or implement them differently. On the other hand, he cites a CAD tech guru who believes that tolerance issues are the easiest to handle.

I can tell you from personal experience that tolerancing is a huge problem. From the standpoint of meshing, not only do we have to handle tolerances on the CAD level but we also have to tolerance the mesh. Consider a submarine that’s over 300 feet long that includes details like the blunt trailing edge of the propulsor blades. Subs operate at very high Reynolds numbers so when we generate the mesh we have to a) place the outer boundaries “far” away from the hull (increasing the scale of the coordinate system) and b) generate a mesh to resolve viscous boundary layers. The result is a grid with coordinate values and length scales that range over 8 or 9 orders of magnitude – from the smallest boundary layer cell to the outer boundary that’s N hull lengths away.

A Cylinder’s a Cylinder Until It’s a Cone

A subtle source of interoperability problems that’s buried “under the hood” is the issue of how a CAD system represents geometry internally. Yares cites the example of ACIS representing a cylinder as a cone with the implication that other CAD systems might represent a cylinder as something else – a cylinder or a B-Spline.

How does this manifest itself in practice? Here’s an example from our Pointwise software. We start with the ACIS file itself that some application exported and which contains representations specific to ACIS and the originating CAD system. We use CAD readers from CT Core Technologies and the first thing they do is import the ACIS file and store all the geometry in their internal representations. Finally, we have to query the Core Tech kernel, extract the data, and store it in our own kernel which likely uses yet another representation for the geometry. Just like kids sitting in a circle playing the game “telephone”, each hand-off of CAD data from one representation to another is a potential source of error.

Files, Standards, and the People Who Write Them Poorly

Yares touches only briefly on a third error source which is the rather unglamorous upkeep of various CAD importers. For example, Pointwise imports CAD geometry from IGES, STEP, Pro/E, CATIA, NX, SolidWorks, ACIS, Parasolid, STL, VRML – I’m certain I forgot something. Every time the CAD company releases a new version there’s a lag while our partners at CT Core Tech introduce the corresponding reader.

The problem with standard formats like IGES and STEP isn’t necessarily the upkeep. The problem is dealing with systems that write those files with blatant disregard for the standard. I could bore you to death [if I haven't already] with tales of the absolute crap we’ve seen inside IGES files. What I like to tell people is there’s nothing wrong with IGES files, but there’s a lot wrong with many of the people who write IGES files.

So Now What?

You should go back to the top of this article, click on the link to Yares’ article, and read it. As he writes, if you stick with it to the end you’re a CAD nerd. Which I suppose is better than being a mesh nerd.

Later we can talk about technologies like shrink wrapping and defeaturing and why we have our own geometry kernel instead of licensing one from a 3rd party.

Applications

CFD simulation of flow over a Star Wars X-Wing fighter done with Project Falcon in Autodesk Inventor.

• Autodesk’s Project Falcon is now available within Autodesk Inventor for doing things like CFD on an X-Wing.
• CIMdata published a report on CAD Selection Considerations: Dealing with Sophisticated Freeform Shapes. (registration required)
• The Team for Advanced Flow Simulation and Modeling at Rice University is applying CFD to spacecraft parachutes. [It's getting to the point that I get irked if a magazine article isn't immediately available online. The link is to a poor quality OCR scan of the original article from Mechanical Engineering magazine. ME Magazine hasn't posted the article yet so this site is the best link I could find. It's a good article and I recommend that you read it. Also check out the T*AFSM website.]
• NASA has advanced the application of CFD to rotorcraft design.

CFD simulation of a V-22 rotor showing “turbulent worms.”

Business News

• Beginning on 1 March 2013, IDAJ will distribute, support, and jointly develop with ICON CFD products and services centered around the FOAMpro product line.
• CFD consulting firm IDP has been acquired by Rand/IMAGINiT.

Events

• Abstracts are now being accepted for the Symposium on Trends in Unstructured Mesh Generation (aka MeshTrends) to be held in conjunction with the U.S. Congress on Computational Mechanics, 22-25 July 2013, Raleigh, NC.
• ERCOFTAC’s course Transition Modelling II will be held 22-23 May in Munich.
• The 7th M.I.T. Conference on Computational Fluid and Solid Mechanics - Focus: Multiphysics and Multiscale will be held 12-14 June 2013 in Cambridge, MA.

CFD Needs More Pink

My brain has the tendency to find connections where none exist. But some coincidences can’t be ignored. Two CFD-related articles with a common element came to my attention last night, one right after the other.

First, F%^$ Yeah Fluid Dynamics brings us this pink image illustrating how a jet of fluid can bounce off another fluid surface.

Follow the bouncing jet of fluid.

Then what should appear in my RSS feed but a blog post by Mentor Graphic’s Nazita Saye titled Shrink It and Pink It in which she observes that pink is the new black, at least as far as women’s products are concerned. At least that doesn’t extend to CFD where engineers are engineers and a product’s capabilities win out over color. [I'm really tempted to do a parody of marketing CFD to women.]

Pointwise even has its own pink-related eccentricities. The default color used to draw CAD geometries is pink, a choice that goes back to the late 1980s and the reason for which is lost to the sands of time. But whether the CAD is pink or gray or whatever doesn’t make any difference, right?

A wrench in any other color is just as butch, right?

Back in the day our Gridgen software offered the user a palette of precisely 7 colors (one was pink) with which to draw surfaces in the grid and geometry. Ten bonus points go to the first person who can tell me the significance of the number 7 in this regard.

According to color theorists, the color pink represents unconditional love and nurturing. Don’t you think CFD needs more of that? Or I have I been at this business WAY too long?

Stanford ADL SU2 News

The Aerospace Design Lab at Stanford University released SU2 Version 2, their open source, C++ based CFD code. It is reported that SU2 has been downloaded over 2,700 times in the year since its first release.

Notable new features in Version 2 include (but aren’t limited to):

• Better parallelization and multigrid
• SST turbulence model
• Reacting flow models
• Improved grid adaption

The SU2 team presented a paper about their code at the recent AIAA Aerospace Sciences Meeting. Their paper titled Stanford University Unstructured (SU2): An Open-Source Integrated Computational Environment for Multi-Physics Simulation and Design is available for download from their website.

SU2 gradient-based mesh adaption for a Lockheed Martin design. Image from SU2′s AIAA paper.

And to wrap-up SU2 news, CFD Online opened a new forum dedicated to SU2.

Choices, Choices, Choices – How to Mesh for Analysis

Desktop Engineering published the article Meshing Your Design for Analysis: Which Path to Take? in which they discuss with industry representatives the tradeoffs of three different approaches:

• Use CAD-embedded meshing and analysis.
• Use meshing tools native to your analysis package.
• Use specialized meshing tools.

Pointwise’s Rick Matus contributed to this article and spoke about all approaches but, obviously, represented use of specialized meshing tools.

If I was to cite one benefit for each approach they would be:

• CAD-embedded – avoid geometry transfer/translation
• native to analysis – guaranteed mesh/analysis compatibility
• specialized – broad functionality portable to many analysis tools [OK, that's 2. Sue me.]

An adaptive mesh from SolidWorks. Image from Desktop Engineering.

Without meaning to contradict anything said in the article, it’s clear that the demarcations between the three approaches aren’t necessarily all that distinct. Native and specialized meshers have strong CAD import capabilities. CAD-embedded meshers aren’t always as simplistic as folks think. And specialized meshers have customization and automation features that allow non-expert use.

What’s also unsaid is that the mesh must provide a solid foundation for your analysis – the needs of the software itself and your needs for simulation results. If your solver needs hexes and the mesher doesn’t make them it doesn’t matter what other attributes it has. If you need resolution of viscous boundary layers to compute separation or heat transfer and your mesher only makes uniformly-spaced meshes you can’t use it.

[Comment: At the top of the article there's an image of what looks like an overset mesh and flow solution for a weapon dropping off the pylon of an aircraft. However, the image is so terribly distorted that all the grid lines have dropped out making the image a waste of pixels. You'd think that the magazine would know how to avoid this and/or have fixed it by now. For example, the image appears to be in JPEG format which, because of the compression, is an absolute no-no for engineering graphics with lots of fine lines. I'm also willing to bet they scaled the image up which is a losing proposition, literally and figuratively.]

Meshing for FEA

Desktop Engineering also ran another meshing article, this time focused on FEA. Meshing for FEA is based on material from NAFEMS’ Intro to FEA course and includes several interesting factoids.

• In some cases meshing can account for 80% of project time.  [I found this surprising for FEA where I thought that meshing was much more mature and automated.]
• The practical performance limit for FEA meshes is 5 million elements.
• Hexes and quads are preferred over tets and tris for accuracy reasons. If you must use a tet for reasons related to meshing time, never use a linear tet – use one with 10 nodes.
• Badly shaped elements effect the accuracy of the FEA results.
• And of course, CAD geometry can have an adverse effect on meshing.

Best of all, the author advises that you limit the amount of time you spent on meshing because meshing is such a “therapeutic pastime” it’s easy to get carried away. I like where his head’s at!

News in Brief

• CFD Online opened a new general forum for visualization.
• The OpenFOAM Foundation has opened a repository for unsupported contributions to the code.
• Siemens PLM Software released Femap Version 11 including the ability to create geometry from legacy meshes, better XY plotting, and improved NASTRAN compatibility.
• Beta CAE released versions 14.0.0 of ANSA and μETA for pre- and post-processing, respectively.
• 30 billion cells in 120 seconds?  That’s what FieldView was able to do for a researcher at the University of Tokyo who’s computing 10-20 high fidelity CFD runs per night.
• Can Carnegie Mellon’s Capability Maturity Model for software development be molded into a Simulation Maturity Model? [This is an old blog post rediscovered in Altair's year-end summary.]
• Can a wind turbine operate efficiently when installed in the middle of Case Western Reserve University’s urban campus? (Full paper available at the link.)

CFD simulation of a wind turbine in an urban setting. Image from COMSOL.

Trelis for Meshing

Computational Simulation Software (aka csimsoft) announced the release of Trelis 14.0 – “powered by CUBIT” – for mesh generation. According to their website, after more than two decades of developing CUBIT in conjunction with Sandia National Labs and distributing CUBIT commercially, Trelis is a new product with CUBIT at its core with csimsoft’s upgradges.

[It's not clear to me at this time how CUBIT, Trelis, and the announced (but as of yet unseen by me) open source version of CUBIT are related. Is this the beginning of a divergence? Or will all 3 move forward in lock-step?]

Drop a red hot ball of nickel into water? Let me sing you the song of my people.

When a red-hot ball of nickel is dropped into water it’s surrounded by a layer of bubbles and makes a pretty interesting sound. Click the image for the video.

What do you see are the biggest challenges facing CFD in the next three years?

I see several bottlenecks in our ability to design, by computational means, the aerospace systems of the future:

1. Improved physical models including unsteadiness (turbulence, transition, acoustics, structures, combustion)
2. Seamless multi-disciplinary/multi-physics coupling at high fidelity
3. Harnessing the phenomenal computational power that will be available (in all steps of the analysis/design process, from mesh generation and adaptation, to solution and post-processing) and
4. Ensuring that both numerical errors and model-form uncertainties are appropriately quantified and handled.

John: Is that a prioritized list? If it is I’m glad to see turbulence modeling listed higher than meshing. Seriously, you include meshing from the standpoint of computational efficiency rather than issues of dealing with CAD or accuracy. How did you reach that conclusion?

Juan: They are not in any particular order: all of these challenges will need to be met (in the next 10-15 years) if we are to bring CFD to the next level. The issues in meshing and geometry interfaces will be fundamental, particularly for streamlining industrial processes. Ready-to-mesh CAD geometry, the ability to drive the design parametrically, and effective mesh adaptation procedures (to reduce numerical error) in highly-parallel environments must be available to accomplish significant improvements in efficiency.

What are you currently working on?

Our lab focuses on developing design methodologies for multi-disciplinary aerospace systems. We are currently working on uncertainty quantification of hypersonic air-breathing propulsion (at our PSAAP Center), low-boom supersonic aircraft, and high-speed re-entry vehicles, among other things. Over the past two years, a good portion of our lab, led by Dr. Francisco Palacios, has developed an open-source suite of tools for the analysis and design of problems governed by PDEs. The suite is named SU² (Stanford University Unstructured) and most of the applications so far can be found in the field of Computational Fluid Dynamics. SU² includes a flow solver, an adjoint solver to compute sensitivities, the ability to adapt the computational mesh, and both shape parameterization and optimization capabilities (all scripted using the Python language) so that users can analyze, optimize, and design out of the box. We have seen more than 4,000 downloads since the first release, and more than 40,000 visits to the SU² website (su2.stanford.edu). Our hope is that engineers and researchers around the world will contribute to developing additional capabilities in the source code so that design optimization capabilities can be accessed by anyone in the world.

SU2 solution for the DLR-F6. Mesh from Pointwise.

John: Tell me more about how you arrived at the decision to release SU² as open source. There are a lot of open source CFD codes out there, with OpenFOAM the most obvious example. How does SU2 fit into that universe, who is your target user, and where do commercial tools fit into that world?

Juan: That is an excellent question: why another open source solver? Why not just start with OpenFOAM and contribute to it? There are several reasons that I list below:

1. Our main area of interest requires the ability to (a) solve compressible flows over a very broad speed range, and (b) the ability to do design optimization using gradient-based algorithms. We could not find these capabilities in other open source solvers/frameworks.
2. Frankly, believe it or not, in a university laboratory we are also very concerned about the efficiency with which students pursue their own research projects,Must every student write his/her own solver from scratch? This is very inefficient. Can you leverage large portions of the infrastructure and develop the ones you need? Thus SU².
3. Our work involves complex configurations of industrial interest and the multi-block (face matched) mesh generation process in our previous solver, SUmb, was slowing our students down. A focus on unstructured meshes made sense.
4. We have been pursuing more multi-disciplinary problems that required additional equation sets (PDEs) to be solved. Leveraging the infrastructure that already existed was very helpful.

Overall, the effort to develop a new solver and optimization environment is beginning to pay off: several students in our group are sharing the development effort and the benefits of more rapid testing of research ideas.

Mach contours around a launch vehicle. CFD by SU2, mesh by Pointwise.

How did you get to be where you are today?

I would say it has been a combination of timing, luck, and hard work. I started my freshman year of college at the School of Aeronautical Engineering in Madrid, Spain. I then transferred to MIT, where I completed a bachelor’s degree. Then a master’s and Ph.D. degrees at Princeton University and, since 1997, I have been teaching at Stanford University (Department of Aeronautics & Astronautics). When I first left Spain for Cambridge, MA, I expected it to be for a period of one year. Twenty-five years later I am still around!

Who or what inspired you to get started in your career?

I am and have always been an aerospace nut. As a child, I wanted to be an astronaut. But at the sweet age of eight I realized that (a) I wore glasses, and (b) I lived in a country without a space program! I decided that the next best thing was to design the vehicles that flew in our atmosphere and that went into orbit. There were lots of people that inspired me to pursue my dreams: teachers in school, professors in college, fellow students, colleagues in industry, even a neighbor who built the most phenomenal R/C aircraft you have ever seen!

John: I find a lot of CFD people of a certain vintage were inspired by the space program. What effect do you think the current state of the U.S. space program has on tomorrow’s engineers? For example, I’ve listened to academic briefings that directly blame cancellation of the Space Shuttle for a drop in aerospace engineering enrollment.

Juan: Space and aeronautics programs in the U.S. (science and exploration, manned and robotic, space and aeronautics, government and private industry, applied and fundamental research) continue to inspire new generations of scientists and engineers. When you hear about the successful landing of the Mars Science Laboratory and the adventures of the Curiosity rover on the surface of Mars, you cannot help but feel proud of being a member of the human species! Why? Because these are wonders of science and engineering the sole existence for which is to improve knowledge and the quality of life for everyone on Earth. Though the end of the Space Shuttle era may have brought some sadness to many of us, the truth of the matter is that every week I hear of something new going on that can be as powerful a motivator as the Space Shuttle was in its time.

More CFD goodness from SU2.

What advice do you have for young people entering the field today?

Do not ever stop pursuing your dreams, and do not ever let anyone tell you cannot accomplish something. Think, plan, and try to do something. If it does not work, try again. And if it still does not work, keep trying until it does. Nothing is too difficult to be achieved.

John: Since you work daily with young people, I’ll ask you about something that’s become a pet peeve of mine and that’s the mystery surrounding younger generations: Gen X, Gen Y, Millennial, etc. I think that statements to the effect that younger generations are mysterious beings that need to be treated differently are categorically false. I think they’re more or less like every preceding generation and all that’s changed is the tools they use (e.g. mobile computing, social applications). Would you agree or disagree with that?

Juan: I am completely with you. I am tired of hearing that the latest generations have shorter attention spans, are not as focused/driven, or require more spoon-feeding in science and engineering. Nonsense! Every day I work with young people who are just as curious, driven, and hard working as you or I ever were. They learn differently, they communicate differently, and have slightly different team dynamics, but so did we!  I think the pace of knowledge is accelerating and the current generation is doing an admirable job of grasping all the opportunities. Aerospace has a bright future.

How do you know Pointwise?

I have been a Pointwise / Gridgen user since 1995. At that time, we were attempting to do aerodynamic shape optimization on complete aircraft configurations (both transonic and supersonic) and Pointwise was the company whose products we used. In our SU² development team, Pointwise is widely used for all types of applications. The ease of gridding lets us focus on what we do best: analysis and design optimization.

John: I was especially happy with how quickly your team at the ADL jumped on Pointwise and customized it with a plugin for compatibility with SU². That’s an example of why I like working with younger engineers: they have fewer bad habits to break.

Juan: Two things. Firstly, indeed, when students thought it was a pain to dump meshes from Pointwise in a given format (say CGNS) and then convert them to an SU² format, they just looked for a better way of doing it. It was obvious to them that adding to the way that Pointwise dumped meshes was the most efficient thing to do!  But, secondly, Pointwise responded admirably: within a week we had a capability in place. Thanks!

Can you share with us your favorite tools and resources that help you get your job done?

• For code development, there is hardly a better environment for OS X than Xcode (https://developer.apple.com/xcode/). It makes developing C++ code so much easier!
• I have to give a lot of kudos to the Python (http://www.python.org/) development team. What a simple and wonderful way to couple multiple high-fidelity solvers, even in a highly-parallel environment, with a few lines of code.
• For debugging, Totalview (http://www.roguewave.com/products/totalview.aspx) is amazing. I cannot believe the amount of printf() statements that I wasted in my life before I discovered Totalview.
• For visualization of results, I miss the capabilities of the IBM Data Explorer (which then became OpenDx). I enjoy using Ensight (from CEI http://www.ceisoftware.com/ensight10/) a lot these days.

John: I’m going to guess that your people at the ADL use Pointwise on the Mac. Is that working well for them?

Juan: Yes. Most of our students run on Mac OS X and Linux. Pointwise for the Mac has exceeded our expectations. We are very glad that you have decided to support the Mac as it is fairly pervasive in academic/research circles.

John: As you know, our Glyph scripting language is based on Tcl. Several people have recommended that we include Python bindings for Glyph. How do you think that would benefit script writers?

Juan: Python is one of the languages that we love in our lab. It allows us to prototype code very quickly and can interface with Fortran, C, and C++ for compute-intensive tasks. Having Python bindings for Glyph would be simply amazing. I will let you in on a little secret: the next generation loves Python. Why? I am convinced that Python’s popularity comes from the students’ familiarity with Matlab, which has become the tool of choice in the vast majority of undergraduate aerospace programs around the country.

If we were to come visit you where’s a good place to go out for dinner?

You would not be disappointed. The Bay Area is home to some of the most outstanding restaurants in the world. In Palo Alto, CA, I would recommend Tamarine (http://www.tamarinerestaurant.com/) if you like the flavors of the Far East, and in Menlo Park, CA, I enjoy Madera (http://www.maderasandhill.com/) for a true California cuisine experience.

John: Sounds great, Juan. Thanks for taking the time for this interview.

Software

• Stanford’s SU2 open-source CFD code is now maintained on GitHub. Visit the repository here.
• CEI announced that EnSight now supports TRK (particle track files) from STAR-CCM+. (Be sure to watch the videos.)
• A brief article about acoustic simulation of turboprop noise.

Included here primarily for the mesh. This is an aeroacoustic simulation of aircraft cabin noise from turboprops. Image from SAE.

Business

• If you’ve ever struggled to make sense of the business side of CAE you’ll probably want to take the time to listen to this interview with Monica Schnitger on the Life Upfront podcast. [Although I'm dubious that earnings season is more exciting than football season.]
• Forbes delves into the issue of reinventing CAD for the cloud. [Warning: the term democratization is used.]

Applications

Airfoil simulation done on a GPU. Image from NVIDIA.

• Students at TU Clausthal used a GPU for transient airfoil simulations on meshes with 300,000 cells.
• Symscape describes the CFD simulation of a pitot tube and manometer.
• CFD will be used to study sand erosion.
• Anyone looking for aerodynamic data to valid their CFD should go immediately to NASA’s website for the Common Research Model (CRM).

NASA CRM model installed in a wind tunnel. Image from NASA.

Fluids and Crystals

We know what fluids are and we know that crystals are rigid solids with some very interesting material properties. Furthermore, we all know what LCDs are. But what about a crystalline liquid?

Using a computer simulation, physicists at La Sapienza University in Rome showed that if you chill a colloid in just the right way you get a stable fluid that also has the properties of a solid, like a crystal. The technical paper is available at Nature Physics, registration required.

When the Fluid is the Computer

Having just mentioned LCDs, the segue to this news item is perfect (even if the fluid is only the display and not the entire computer). The AquaTop projects images onto a fluid surface while a Kinect tracks your interactions with the fluid and hence the projected display.

A recent article complained that engineering students graduate without ever getting their hands dirty building things. I wonder if those employers will be happy if students are getting their hands wet?

The AquaTop computer display developed by Tokyo’s University of Electro-Communications is truly what you’d call an immersive environment. Image is a screen capture of a video from CNET.

Software Releases

• Intelligent Light announced FieldView 14 including 400-times faster unsteady particle visualization and 8-core usage standard.
• CONVERGE Studio now fully integrates EnSight for post-processing.
• Convergent Science announced CONVERGE in the Cloud, a pay-per-use implementation of CONVERGE CFD.
• Daat Research announced a 20 times speed-up of solver performance in Coolit v.13.
• Beta CAE released ANSA/μETA 14.2.1, a maintenance release.
• Autodesk Simulation CFD 2013 SP1 was released.

Jobs

• Pointwise wants to hire a Technical Support Engineer.
• MSC.Software wants to hire a Principal Software Engineering for mesh generation.

Pointwise and GridPro Collaborate

The recent release of Pointwise Version 17.1 R4 includes file-level compatibility with the GridPro structured grid generator. Pointwise can export structured and unstructured surface meshes to GridPro’s fixed surfaces file format for use as geometry in GridPro. Pointwise can also import GridPro’s volume grid files so you can modify or add other grid to them (to make a hybrid mesh, for example).

Starting with a CATIA model (gray) in Pointwise, an unstructured surface mesh was generated and exported to GridPro for use as geometry. GridPro created a structured, multi-block hex grid near the blades, which was exported back to Pointwise for addition of the outer unstructured mesh.

You might think that two competitors collaborating is odd. But it makes good sense for users of both tools. A GridPro user can take advantage of Pointwise’s native CAD import and surface meshing to prepare geometry. And a Pointwise user can add unstructured and hybrid mesh to a multi-block structured grid from GridPro. And even though both programs have structured grid generation capabilities the two approaches are quite complementary.

Also included in Pointwise V17.1 R4 is a native interface to the DLR TAU CFD solver and an updated OpenFOAM interface that now supports cell sets and zones.

• The announcement of Pointwise V17.1 R4
• www.gridpro.com

Wheeling and Dealing

• CD-adapco and CCTech announced a partnership as “global education partners for CFD training through LearnCAx.”
• ICON and FRIENDSHIP SYSTEMS announced a collaboration to deliver CFD tools, optimization tools, and consulting to the marketplace.
• Meteodyn acquired the CFD code MIGAL-S from Michael Ferry R&D.

Applications

• Symscape computed the effects of a car’s rear wing on downforce.
• More CFD for bicycles: The new Alize bike and the new AiR/TTE were both designed with considerable thought to its aerodynamics including the use of CFD.
• CFD for carbon black manufacturing.
• Cool video of fluid sloshing inside a tanker truck. CFD by Autodesk.
• Ever wonder how a Dyson Air Multiplier works? [No CFD in the article but I'm willing to bet that it was used in the design of this thing.]

Tank sloshing simulation performed using Autodesk Simulation CFD 2014.

Read & Discuss

• The folks at Convergent Science are all about automating mesh generation as noted in their recent blog post, Automatic (Meshing) for the People. They quote Habashi (we “cannot let the user decide where to generate and concentrate points.”) and cite the “school of thought that believes that making a mesh by hand is essential to achieving an accurate solution.” [In my experience that's half true. No one wants or needs to hand craft a mesh. (Although it sure can be fun.) But to most people, automatic mesh generation means "make a mesh automatically and exactly the way I would have done it myself."]
• Katate Masatsuka likes CFD. You can download his 299 page book I Do Like CFD (sponsored by Software Cradle) or buy a printed and bound version for a nominal fee.
• To add to your reading, NAFEM’s has revamped their Benchmark Magazine and now provides it online for free. (Registration required.) This month’s article on Icons of CFD features Antony Jameson.
• Design News writes about Altair’s automotive-oriented Virtual Wind Tunnel.
• Videos and documents from last month’s SU2 and OpenMDAO workshop are available online.

Awards and Honors

• Reaction Design is up for a Most Innovative New Product award (San Diego’s tech industry’s version of the Academy Award^®) for their FORTE CFD – Soot Prediction. [I challenge you to find "Academy Award" and "soot" in the same sentence anywhere else.]
• Two of the five winners of Computer Weekly’s European User Awards for Data Centre involve CFD.

Lattice Gases and Conformal Maps

This article sprays more mathematical terminology than former NFL headcoach Bill Cowher sprays spittle during a sideline tirade. So I will rely on smarter folk to fully enjoy Lattice Gases and Conformal Maps from the Complex Projective 4-Space blog. [My one takeaway was the great analogy of the Schwarz-Christoffel mapping as fitting a square peg into a round hole. Be sure to click on some of the linked-to articles for animations and other cool stuff.]

Mandelbulb Fractal. I have no idea. Image from Complex Projective 4-Space.

Software

• The SU2 CFD solver can now be run on the SimScale platform.
• Materialise released Magics 18 for working with discrete data for 3D printing.
• Beta CAE released ANSA v14.2.2.
• Siemens PLM released Femap 11.1. Videos of the new features are available here.
• If nothing else, Autodesk’s Project Shapeshifter shows what kind of 3D interaction can be done with a cloud-based application. At best, you can create and download 3D printable models.
• Lattice Technology released a new version of XVL Player, a free product for viewing 3D datasets.

Autodesk Project Shapeshifter. [I have no idea what I'm doing.]

Jobs

• BMW in Munich has an opening for a Development Engineer in CFD Simulation.
• There’s an opening for a CFD Process Engineer in London.

Applications

CFD solution for a ship hull at 45 degrees of yaw. Image from Marine Link.com.

• If you have a tug boat you want to get certified, you can now do that with CFD and without extensive testing.
• Desktop Engineering writes about where you might consider running your CFD calculations: on a your desktop, on a cluster, or in the cloud.
• CD-adapco has made available many videos of presentations from their STAR conferences. (registration required)
• You can read the paper and watch the presentation by ATA Engineering on multi-physics simulations of a hypersonic vehicle. (From the Simulia Community Conference, registration required.)

CFD solution for a notional hypersonic vehicle showing Mach number on the symmetry plane and temperature on the vehicle. Image from a paper by ATA Engineering.

Viz, Hardware, & More

• Two notable items from Tecplot:
  • Tecplot shares their version of the chicken and the egg story in describing how their new, high-performance “subzone load on demand” feature works.
  • Their insights from their visit to the IEEE Vis Conference involve hardware’s impact on vis [viz?].
• AMD announced the FirePro S10000 supercomputing graphics card with CFD as one of its targeted applications.
• Are we really at the dawn of a Napster era for 3D content? And what about a “Redoubled effort on community sourced 3D reconstruction libraries and application software (e.g. Point Cloud Libraries and Meshlab), with perhaps even an attempt made to commercialise these offerings (like the Red Hat model).”
• The deadline for submitting abstracts for the ASME 2014 Verification and Validation Symposium is 26 January.
• Microfluidics Weekly is a new publication from the folks at CFDpaper.com.

Our Lady of the Grids

Structured grids (i.e. mapped meshes for you FEA folks) show up in the darndest places. This time it’s a window at the Church of St. Martin in the Fields in London. The artist, Shirazeh Houshiary, said about her work “This tension fascinates me and it’s at the core of my work.”

Since she mentions tension she must be more familiar with meshing than I thought. Also note that this is obviously a high order mesh as indicated by the curved edges of the cells around the central ellipse.

The east window of the Church of St. Martin in the Fields, London, was designed by Shirazeh Houshiary. Image from My Modern Met.

Stanford Updates SU²

The Aerospace Design Lab at Stanford University last week announced a new release of their open source CFD code, SU². This new version, called “Eagle” or v3.0, is focused on detailed RANS validation and accuracy improvements.

In addition, they have released SU² Educational v1.0, a simplified version of the code targeted toward students who want to learn compressible CFD from a well-organized code and toward those users who want accurate 2D solutions. A typical target application is airfoil analysis.

More information about SU² can be found at su2.stanford.edu.

This SU2 simulation of the DLR-F6 geometry from the 3rd Drag Prediction Workshop demonstrates the improved accuracy. Image provided by Stanford.

Things to Read & A Job

• “Social media is a hot topic these days, even among engineers.” [That's kinda like saying "Hmm, this email thing seems to be catching on." Plus, I'm not confident of exactly how enthusiastically engineers have embraced social media. Regardless,] Machine Design published a great resource, The Best of the Web for Engineers, that lists blogs, tweeters, websites, groups and forums that run the gamut from engineering ethics to mechanical design. [And the answer is no. I checked.]
• will.i.am is now 3D Systems’ chief creative officer. [Does anyone think this stunt has any redeeming qualities?]
• Meshing guru Jonathan Shewchuk shares tips on Giving an Academic Talk. [These tips apply beyond academia.]
• From LinkedIn we learn that MSC still has an opening for a Lead Software Engineer in mesh generation.
• Think of CFD as a way to find mistakes in a design before someone loses an eye.
• Desktop Engineering delves into the data monster that is simulation visualization.

The computation behind this flame trench simulation by NASA took a week on a 960 core supercomputer. Image from the NAS flickr page. Click image for video.

Meshing

• In Part 1 of a series on Accuracy and Checking in FEA, we learn important things about the mesh.
  • Don’t rely on your eyeball to assess mesh quality. Use your software’s built-in mesh checking tool.
  • Be aware that how your mesher computes quality metrics may differ from how your solver computes the same metrics.
  • The specific mesh quality metrics on which you rely vary depending on your application and your solver.
  • Gaps (usually the result of gaps in the underlying geometry model), normal vector alignment, and boundary condition application should all be thoroughly checked before beginning your analysis.
• Meshing researcher Daniel Zaide adapted his edge insertion technique to reproduce paintings in mesh form. On his webpage there’s a video (currently offline but soon to be fixed) and a GIF illustrating the meshing of Paul Klee’s 1914.

Events

• The 16th International Conference on Geometry and Graphics will be held 4-8 August in Innsbruck, Austria. This event is sponsored by the International Society for Geometry and Graphics (isgg.net), not to be confused with the International Society for Grid Generation (isgg.org), whose website doesn’t work anyway.
• Eindhoven University of Technology is offering a 6 week course on Sports and Building Aerodynamics.
• Taxal founder, Allan Behrens, will give a keynote presentation at this year’s Collaboration and Interoperability Congress.

CFD simulation of Monash University’s Formula SAE car in a turn with turbulent kinetic energy shown. Image from the Leap CFD blog. Click image for full article.

Software

• DHCAE Tools announced an update to CastNet, a GUI environment for OpenFOAM.
• Symscape announced the release of ofgpu v1.1, a GPU linear solver library for OpenFOAM.
• A new version of OpenHyperFlow2D is available.
• Improve performance by a factor of 5-8 with the new FieldView parallel export in ANSYS Fluent 15.

Wow. So color. Much motion. Amaze.

As the tweet said, don’t blame me if you spend all afternoon playing with AeroDoodle, CFD in your browser, from Swansea University. [And yes, the first thing I did was doodle "my" initials.]

AeroDoodle – click to go to the site

[This is the brief "even I have to do real work every once in a while" edition.]

News

• The UberCloud HPC Experiment has become the UberCloud Marketplace, a cloud-based CAE service.
• A CFD consultancy in London has an open position for a CFD specialist on their environmental team.
• The text Introduction to High Performance Technical Computing is freely available online.
• NAFEMS published volume 10 of the International Journal of CFD Case Studies.
• Virtual Grid released VRMesh v8.0 for point cloud processing.
• Here are a couple of articles on the proposed solution of the Navier-Stokes existence and uniqueness problem: from New Scientist and The Blaze. [As originally seen on FYFD.]
• Desktop Engineering writes about the appification of CFD or more specifically the browser-based CFD applications from Altair.
• The SU2 paper from AIAA SciTech 2014 is now available online: Stanford University Unstructured (SU2): Open-source Analysis and Design Technology for Turbulent Flows.
• CEI’s EnSight was part of the CFD toolkit used to improve the performance of a first-place Reno air racer.

Evolution of the performance improvements to the Cassutt racing aircraft. Image from CEI.

Mesh Generation Deja Wha?

We learn many things from this overview of mesh generation in CFD. Much of what we learn is unusual. And much more sounds eerily familiar. Here’s some of the unusual stuff:

• “three-dimensional CFD renderings” are the most preferable form of mesh.
• CFD comes in 2D, 3D, 4D, and 5D forms. [Why stop at 5?]
• To achieve the best CFD results “it is recommended to outsource professional services for mesh or grid generation.”

And that image of a structured, multi-block grid for the Aachen turbine, I swear I’ve seen that somewhere before.

Git Yer Meshing Kicks

Do you think you’d generate better meshes while wearing a pair of New Balance 890v4? Honestly, it probably wouldn’t hurt.

Software

• STAR-CCM+ v9.02 is due to be released at the end of February and CD-adapco has been offering previews of new features including volume rendering.
• GPU acceleration of OpenFOAM can be had using Culises 1.1 from FluiDyna.
• AcuNexus is now available through the Altair Partner Alliance. The software, a preprocessor for CFD, uses a technology called abstract modeling to allow for rapid geometry prep, meshing, and run-setup during simulation based design.
• SU2 Educational v1.1 is now available from Stanford Univ.
• The OpenFOAM Foundation released OpenFOAM 2.3.0 with improvements to multiphase modeling, discrete element modeling, thermal modeling and more.
• Autodesk MeshMixer 2.1 is now available.

Volume rendering of combustion chamber temperature. Simulation and visualization from STAR-CCM+ v9. Image from CD-adapco.

Events

• The 2014 Code_Saturne User Meeting will be held on 02 April in Chatou, France. Registration is here.
• SC14, the supercomputing conference, is now accepting technical program submissions. Abstracts are due 04 April. The conference is 16-21 November in New Orleans.

Jobs

• Pointwise has openings for summer interns in both product development and technical support in Fort Worth, Texas.
• Exa has multiple internships for application engineers available in both the Detroit and Boston areas.
• CD-adapco seeks a senior software developer in electromagnetism in the Austin, Texas area.
• A company presumed to be CD-adapco has multiple openings for mesh generation software engineers at multiple locations.

Applications

Caedium CFD solution for internal flow with geometry defined by a solid model. Image from Symscape.

• STAR-CCM+ is used to simulate the production of pharmaceuticals using DEM.
• Reverse engineering and meshing of ant anatomy using Simpleware.
• Symscape writes about solid modeling in CFD.
• I would like to hear from the “experts in fluid mechanics” who contributed to the research on the perfect way to hold a cheeseburger to keep it from dripping and falling apart.

Just a Cool Photo of Sea Foam

Photographer Ger Kelliher snapped this rather cool photograph of sea foam. That’s all. I just thought it looked nice. I’m certain FYFD can explain what sea foam is and how it is formed. During my rather limited beach excursions I’m mostly looking for sea glass. [Too nerdly?]

Sea foam photograph by Ger Kelliher. Image from Colossal.

I can find inspiration for projects just about anywhere. While many ideas are fleeting and only grab enough attention for a day or two of work, some stick around and snowball into interesting projects. This is a look at one of those ideas turned projects, the idea that I could run a CFD calculation in the palm of my hand.

The idea for this project started to materialize back in October after receiving an Arduino Uno for another project I was working on. If you haven’t seen it, the Uno is small, about the size of a credit card. It got me thinking, what if I could run CFD calculations on a computer about the size of the Uno. A phone was the logical choice. But compiling something like OpenFOAM for an iPhone or an Android sounded too daunting to even consider. What about the Raspberry Pi?

The $35 Raspberry Pi, developed by the Raspberry Pi Foundation, first launched in the spring of 2012 with 100,000 boards shipping the first day! The goal was to bring an affordable computer into the classroom and teach children the mechanics of computing. But hobbyists had their eye on the intriguing little board that could pump out 1080p video and interface with a number of sensors and other devices. Now, two years after the launch, there are more than 2.5 million Raspberry Pis in the wild.

The credit card sized $35 Raspberry Pi.

The Tweet

After doing the research I decided that I’d hold off on the Pi for a while. Then, in early February, a #SimulationFriday post caught my eye. It was a tweet by Momentum Analysis with a picture of the driven cavity OpenFOAM case being run on two Raspberry Pis!

A two Pi cluster assembled by Momentum Analysis. Image by Momentum Analysis.

An aside, #SimulationFriday is a great hashtag on Twitter where engineers post simulation photos and videos every Friday.

The guys at Momentum Analysis had used an OpenFOAM build provided by Rheologic. Finally, there was a build available for the Pi and I no longer had to worry about compiling it on my own. I could get a Pi and be up and running in no time!

A couple of days later, Momentum Analysis wrote a great how-to blog article about setting up what they refer to as a twoPi cluster. In the article they discuss how to setup the Pi, get the OpenFOAM binaries, and even described some of the tests they performed.

Ok. It was time to get a Pi of my own.

I should mention, not long after their post, I stumbled upon another article about a 40-node Raspberry Pi cluster here in the Dallas/Fort Worth area. The build quality is incredible and I encourage you to check out the video below.

The Pi

I did a lot of research before I purchased a Raspberry Pi. What I learned was that while the board is around $35, the accessories can add up. That is unless you have chargers, cables, and keyboards at home. After looking around I knew what I needed and where I would purchase everything. I settled on ModMyPi. ModMyPi started out manufacturing cases for the Pi, but quickly thereafter began selling a range of accessories. And while they aren’t affiliated with the Raspberry Pi Foundation, they donate 5% of their profits back to the foundation.

Rather than purchasing one of their kits, I decided to stick with the bare essentials and just find what I didn’t already own. Below is a list of everything I purchased from ModMyPi if you’re interested in pursuing the same experiment. Note, prices have increased slightly since I bought these items. If you register and follow them on Twitter you’ll get a discount.

• Raspberry Pi – Model B
• 16GB Samsung Micro SD Card Pre-Loaded with NOOBS (Class 10 UHS-I)
• Cyntech Blackberry Raspberry Pi Case with SD Card Cover
• HDMI to HDMI Cable 2m V1.4 (Gold Plated)
• Raspberry Pi Heat Sink Kit

The Model B Pi comes with 512MB of RAM opposed to the Model A which only has 256MB. This is important for both compiling software and running CFD calculations. I elected to spend a little more on a high performance SD card with NOOBS preinstalled. The NOOBS (New Out of Box Software) package allows for easy installation of many supported Linux distributions, including the official Raspbian distro based on the popular Debian OS.

The heat sinks are interesting. I wanted the ability to overclock the 700Mhz processor to 1Ghz without significantly reducing the life of the Pi. While the heat sinks don’t dissipate that much heat, they do look pretty cool.

Three small heat sinks attached to the board.

OpenFOAM for the Pi

Everything arrived last week, so I’ve only had a few days to scratch the surface. But, the first thing I did was load up the Momentum Analysis blog article so I could configure my Pi to run OpenFOAM. After applying all the necessary updates and playing with a few settings, I downloaded OpenFOAM and had the cavity case running in less than an hour. I was running OpenFOAM on a Raspberry Pi. I was able to run a CFD simulation on a device that fit in the palm of my hand. Momentum Analysis deserves a big thanks as their instructions were spot on. Thank you guys!

Running a CFD calculation in the palm of my hand.

A couple of days later I decided to run a Pointwise generated mesh in OpenFOAM on the Raspberry Pi. I ran a steady-state RANS calculation for the NACA 0012 at an angle of attack to the flow. The solution converged in five minutes. I was ecstatic! Not only could I run CFD problems on the Raspberry Pi, but I could run our meshes on the Pi.

If you’re interested in this case, you can download it and try it yourself.

The velocity field for a NACA 0012. This solution was computed by the Raspberry Pi.

SU2 for the Pi

I had accomplished my goal. I ran a CFD calculation in the palm of my hand. But, I couldn’t shake the fact that I hadn’t really done anything new. The Momentum Analysis guys already did this…in parallel. What could I do differently? What about a different solver? Enter SU2.

A couple of years ago, a group from the Aerospace Design Lab in the Department of Aeronautics and Astronautics at Stanford University released an open source CFD solver. The Stanford University Unstructured software suite, or SU2, is a collection of C++ tools for solving partial differential equations, including CFD problems. The team released version 3.0 of the code in January of this year.

Over the last few weeks I’ve been exploring SU2 for some in-house CFD work, so I’m somewhat familiar with the code and can build it reliably. So, I decided to download the source on the Raspberry Pi and attempt to compile it. My new goal was to package up the SU2 binaries for the Raspberry Pi and run the NACA 0012 problem. Easier said than done.

I wasn’t looking to do anything fancy, so a basic single-threaded compile is all I needed. I followed the well written installation guide provided by the SU2 developers and configured the makefile using only the prefix argument followed by issuing the make command to compile the source code. About 30 minutes into the build the Pi threw up a cryptic error message. Shortly after that, all the applications crashed and the GUI was unresponsive. Unfortunately, the Pi is not equipped with a power switch, so turning off the device is just a matter of unplugging the power, about all I could do at this point.

I reconnected the power to turn the Raspberry Pi back on and was greeted with a kernel panic. Wonderful.

Unplug power. Reconnect power. Kernel panic.

Unplug power. Reconnect power. Nothing. Now the Pi would no longer boot.

I pulled the board from the case, tested the voltage using the two contacts on the board itself. No power. It turns out a fuse had blown and needed a few minutes to reset. Great. Long story short, this process repeated itself a half-dozen times followed by running the fsck utility.

The problem was either the SD card or the power supply. My guess was the board, ethernet cable, HDMI cable, SD card, and USB keyboard dongle were pulling more current than the ASUS Nexus 7 charger could handle. This in turn dropped the voltage below 4.75V and caused some instability. I have since replaced the power supply with a 5V 2.1A iPad 3 charger and have not encountered any stability issues.

Another potential issue was memory. I had been monitoring the memory usage during the build and noticed it creeping up to the 512MB limit. So, using the raspi-config utility I disabled the GUI and gave the GPU access to the minimum amount of memory. Next, I gave the Pi a static IP on my home network and enabled SSH access. The HDMI cable and USB dongle were no longer necessary. Not only did this solve the memory problem, but again I had fewer stability issues.

The Raspberry Pi Software Configuration Tool menu.

Every time I tried something new I reattempted the build, getting further each time. I’d estimate the entire build took around three hours to complete. Once it was finished I ran make install then archived and zipped up the result. I now had a Raspberry Pi Raspbian build of SU2!

The first attempt at compiling SU2 on the Raspberry Pi.

The first thing I did was run through the detailed quick start tutorial to ensure that at the very least SU2_CFD was working. Sure enough, the steady, Euler calculation for the NACA 0012 converged in under three minutes.

The SU2 team graciously offered to host the binaries on their site for download. If you’d like SU2 for the Raspberry Pi, please visit http://su2.stanford.edu/download.html. You may notice there is also an SU2_EDU link for the Pi. It’s coming soon, but more on that later.

Lessons Learned

This was a great project. And while I’m happy with the work that Momentum Analysis and Rheologic have done, I’m glad I didn’t stop with the precompiled OpenFOAM build. It was great tearing through the electronics, decrypting error messages, and learning how to compile and run CFD software on a device that fits in the palm of my hand.

If you are interested in this project and are planning on purchasing a Raspberry Pi of your own, here are a few lessons I learned along the way.

1. Use a good power supply.

I can’t stress this enough. While the Raspberry Pi board doesn’t require that much power, it starts to add up once you plug things in. The Pi calls for a 5V 1A power supply. Most phone chargers will work, but in my experience some are flakey. I recommend going with something stable, preferably 5.25V to account for any slight voltage drops and 2A allowing for more peripherals to be plugged directly into the board.

2. Give the Raspberry Pi a static IP address and enable SSH.

If you plan to do any kind of development or CFD, ditch the GUI for the command line and SSH into the Pi. Telling my router to give the Pi a static IP wasn’t enough, I also had to edit the network interfaces file. Here’s a great video describing how to give your Pi a static IP address.

Also, you’ll need to enable SSH as it’s off by default. This can be done through raspi-config, the Raspberry Pi Software Configuration Tool seen below.

Use the configuration utility to enable SSH through the Advanced Options menu.

3. Expand the filesystem and adjust the CPU/GPU memory split.

If you use the NOOBS package to install Raspbian, the filesystem will automatically occupy the entire SD card. However, if you install the OS in another way, you’ll need to manually expand the filesystem to take advantage of all the memory available on the card. You can also do this using the raspi-config utility. You may also want to give the GPU the minimum amount of memory. This can be done using the same utility.

Expand the filesystem to fill the SD card using the configuration utility.

4. Overclock.

Lastly, overclock. The Raspberry Pi doesn’t generate much heat and doesn’t draw much power. Exploit the efficiency by overclocking. A stock Raspberry Pi runs at 700Mhz. I’ve overclocked the CPU to 1GHz giving it what I’ve been told is an extra 50% more horsepower. This is where the heat sinks come in handy.

Select the desired overclock frequency for best efficiency and performance.

Applications

Screen capture from a video showing CFD simulation of natural ventilation in a steel mill. Video by Moffitt Corp.

• Video of a CFD simulation of using natural convection to cool a steel mill
• Simulation of blood flow in flexible arteries
• Blood coagulation CFD case study
• Experimental and computational work on modeling bat wings in flight.
• Using CFD to study breathing disorders
• Symscape writes about co-processing for transient simulations.
• High Tech CFD lists the advantages of CFD for the HVAC industry.
• On a related note, IMAGINiT lists reasons why CFD is perfect for the building industry.
• And from Design News comes this general CFD advocacy.

CFD simulation of heat coming off participants in a meeting about who’s mostly to blame for CFD inaccuracy. Meshing people on the left, turbulence modeling people on the right. Image from Building Design and Construction.

General Interest

• NAFEMS features an in-depth profile of CFD Icon David Gosman in which we learn two things: what STAR is an acronym for and that he has never run a commercial CFD code. [The link is to a post in the LinkedIn Academic CFD Simulation group. Login required. Article in PDF.]
• Accuracy and Checking in FEA, Part 2 – from Desktop Engineering
• Something only mesh generators will love: After 400 years, another class of equilateral convex polyhedra (e.g. Platonic solids) has been discovered, the so-called Goldberg polyhedra.
• ANSYS continues to be financially successful, earning $861.3 million in FY 2013. [How long until $1 billion?]
• If you’re a student in Maryland interested in studying engineering, you have until 24 March to apply for Northrop Grumman’s Engineering Scholars competition.

Jobs and Events

• Recruiters are posting a CFD Aerodynamicist job in Oxfordshire, UK.
• SunCoke Energy in Lisle, Illinois wants to hire an Aerothermal CFD Engineer.
• The SIMULIA Community Conference will be held 19-22 May in Providence, Rhode Island.

Software

• Introducing Flowsquare, free 2D CFD.
• Dynaflow updated their 3DynaFS CFD software with improvements in bubble dynamics, cavitation and more.
• Onshape, the folks developing what appears to be a cloud-based CAD system, have licensed Parasolid and D-Cubed from Siemens PLM.
• On a related note, Siemens PLM released Parasolid v26.1.
• SpaceClaim released new tools for online collaboration (Live Review) and 3D printing (STL Prep).
• Beta CAE released ANSA and μETA v15.0.1.
• Stanford’s SU2 is now available for the Raspberry Pi [courtesy of Pointwise's own Travis Carrigan]. Travis’ article about the port is now the most highly read article on this blog.
• CUDA 6 is available as a free download for parallel GPU programming.

Abstract Painting as Mesh

Daniel Hill is another artist whose abstract work reminds me a lot of mesh generation. He’s striving to “bring the power of sound into the visual experience.”

Daniel Hill, Untitled 5, 2011

Bonus: What does art have to do with space travel? Plenty, in the case of the NASA Centaur Art Challenge celebrating the launch vehicle’s 50th anniversary.

Software Patents

In a closely watched ruling (maybe only by us software people) the U.S. Supreme court ruled unanimously in Alice Corp. v. CLS Bank that you can’t get a software patent for an abstract idea for the reason that it is simply a building block of human ingenuity. In other words, it doesn’t pass even the first test for patentability let alone those of novelty, obviousness, and vagueness.

This ruling does not imply an end to software patents, only that they must be more substantial than an idea that could be computerized and would actually need to demonstrate improvement to some actual function (i.e. actually be implemented).

Another interesting tangent on this ruling is that Alice Corp. is regarded as a “non-practicing entity” i.e. a patent troll.

Read coverage from:

• The Wall Street Journal
• USA Today
• NPR
• Fortune

Software

• ENGYS announced the release of Helyx-OS v2.1.0, the open source GUI for OpenFOAM.
• A new version of XFlow was recently released. [PDF]
• Foam-Extend 3.1 was released.
• PTC released Creo 3.0 including the ability to import models in other CAD formats.
• SU2 version 3.2 was released.
• CFD Support announced the release of Turbomachinery CFD version 14.06 (based on OpenFOAM).

Applied Math Modeling released CoolSim 4.3. Click image for article. Image from Data Center Knowledge.

Events and Business

• CD-adapco announced a partnership with researchers at the Univ. of Stuttgart for the profiling and benchmarking of STAR-CCM+ on petascale computers.
• Deadlines are fast approaching for the 2014 FLOW-3D Americas Users Conference including early bird registration (01 July), and abstract due date (11 July).
• You have until 31 August to submit your entry to CD-adapco’s 2015 Calendar Contest. Maybe yours will be the one who gets the most social media votes and wins a cool prize.
• The second NAFEMS European Conference on Multiphysics Simulation will be held 21-22 October 2014 in Manchester, UK.
• ESI reported a 7% decrease in Q1 revenue due largely to the company’s shift to service deals. [Nothing reported about OpenFOAM's contributions to their numbers.]

Reading

• Visualising Data shares the best of the visualization web for April 2014.
• The software catalog for 2014 from NASA’s technology transfer program is available online.
• The June 2014 issue of DEVELOP3D is now available.
• ENGINEERING.com delves into ANSYS Workbench and learns about its future, a future that goes beyond cloud and integration and into a fully unified, immersive, multi-physics environment.

Thresholds of Silence

Combining the old and the new, art and science, geometry and aeroacoustics, the Buitenschot Landscape Art Park near Amsterdam’s Schipol Airport uses well planned and deeply cut ridges in the nearby landscape to reduce the propagation of ground level aircraft noise.

Farmers have known for quite some time that deeply plowing a field creates a very quiet landscape. Through study of the noise sources architects designed these V-shaped ridges for the same purpose while at the same time creating a publicly usable green space. Seems like a win-win to me.

The landscape architect calls the ridges the Thresholds of Silence.

Buitenschot Landscape Art Park at Amsterdam’s Schipol Airport uses these ridges to reduce noise pollution. Image from pauldekort.nl.

P.S. Apologies if some of this news is repeated from last week. I was in a rush and didn’t do a good job separating old from new news.

Thoughts

The Virtual Engineer ponders whether we need more standards for CAE interoperability and emphasizes the possible benefits for mobile visualization.

The author answers his own question: “of course.” That’s the wonderful thing about standards – there are so many of them.

There are CAD standards like IGES, STEP, and JT. And we know how well that’s worked out. We could spend days talking about why we still have CAD interoperability problems. [tl;dr Standard files are neither written nor read properly.]

There is a great CFD standard – CGNS. I beg all of you to start using it. But it too has issues. [tl;dr What makes for great portability doesn't necessarily yield great performance.]

And there are all your de facto standard formats: PLOT3D for structured grid CFD results, NASTRAN for FEA results, STL for faceted geometry, etc.

I don’t know enough about visualization standards to know whether we need (another) one. But for CAD and CFD, use the ones we have, and use every ounce of your influence to ensure that everyone uses them correctly, and contribute to the standards organization to ensure the standard is maintained and updated.

What do you think?

News

• New website ConSelf (Consulting by Yourself) urges us to “be prepared for the next CFD solution.” [Mysterious]
• New web search tool (currently in beta) www.3dshap.es promises to help you find 3D designs to print.

Events

• Pointwise and the SU2 Team will be hosting a Joint Workshop on the open source SU2 CFD solver on 29-30 September.
• The JT Open International Conference 2014 will be held in Tokyo on 17-19 September.

Videos

Viscous Stanford Bunnies Falling Into a Pile. Screen capture from the video illustrating multimaterial mesh based surface tracking cited below.

• While “multimaterial mesh-based surface tracking” may seem dry, you have to watch this video (and jump ahead to the 5 minute mark if you’re impatient). Then you can read about this “non-manifold triangle mesh tracking method to simultaneously maintain intersection-free meshes and support the proposed broad set of multimaterial remeshing and topological operations” developed by researchers at Columbia.
• You can watch a video about what’s coming in Autodesk Simulation CFD 2015.
• Another video, this one on CloudFlow, CFD in the cloud.

Meshing and Football?

You never know where meshes are gonna pop up. This past week a group of us from the office took the guided AT&T Stadium Art Tour. Yes, that’s right – an art tour inside the Jones family’s monument to Dallas Cowboys football.  (If you click on the link you’ll see a photo with a nice gray-haired lady at the bottom. That’s Sue. She was our tour guide.)

But the family, with the assistance of outside advisors including Michael Auping, chief curator at The Modern Art Museum of Fort Worth, have amassed an extensive collection of contemporary art installations. Most of these pieces are visible to everyone who attends an event at the stadium (some hang above the concession stands).

So where does meshing come in to play? Jim Isermann’s Untitled (2009-2010) is 4,000 square feet of vacuum-formed styrene mesh loveliness.

Jim Isermann, Untitled (2009-2010)

We’ll post more of the photos from our tour on our Facebook page soon. In the meantime, there’s an app for iOS that will give you a virtual tour of the artwork.

Software

• Here’s this week’s “must click” link: WebGL-based fluid experiment. [Must have a “modern” browser and plenty of horsepower to enjoy the full experience.]
• Maybe our friends who know particle dynamics can validate whether mosh pits are more particulate or fluid.
• What is Caelus? [And how do you pronounce it? KAY-lus.] It’s a fork of OpenFOAM that’s been cleaned up, made easier to install, and supports Windows and Linux. [Full disclosure: The company behind Caelus includes a former Pointwise employee and the current Pointwise distributor for Australia.]
• CD-adapco released STAR-CCM+ v9.06 with a slew of new capabilities in performance, accuracy, and preprocessing.
• Richardson CFD (i.e. UFO-CFD) has a new website.
• Daat Research released Coolit v.14.
• Tech Soft 3D released HOOPS Exchange 2015 for 3D CAD data access.
• DEVELOP3D writes about the latest release of Magics 19 for working with faceted geometry (i.e. STL).
• CFD World wonders why OpenMDAO is open source.
• Fast Company is a bit passive-aggressive in their praise of Vim for text editing by labeling it an ’80s text editor. [Yes, I am trying to provoke a vi/Vim vs. Emacs debate.]

There’s a new release of PyFR, the open source Python framework. Image from pyfr.org. Click image for website.

Art

• Software is now able to determine a painting’s genre and influences 70% of the time.
• We would like to think that artist Janet Echelman uses high performance computing including CFD to design her “living breathing pieces that respond to the forces of nature – wind, water, and light.” (See image below.)

Janet Echelman, Line Drawing, 2006-2007. (Image from echelman.com. See link above.)

Events

• The proceedings of the 23rd International Meshing Roundtable are available online for free via Science Direct.
• You have only until 09 November to submit a design to be 3D printed for the i.materialise Holiday Gift Challenge.
• NAFEMS has begun a Benchmark Challenge Series beginning with one on stress in the center of a square plate. [Hopefully fluids challenges will come soon.]
• A workshop on Uncertainty Quantification in CFD will be held on 13 November in Delft.
• You have until 17 November to enter your simulation images in ANSYS’ 2015 Hall of Fame Competition.
• The proceedings from TFAWS 2014 (Thermal and Fluids Analysis Workshop) are available online. The 2015 event will be held in August at Goddard Space Flight Center.

Applications

• ESI’s CFD software was used as part of a fluid-structure interaction application for sun shades in Medina and Mecca.
• The Tame Aerodynamicist shares an introduction to the finite volume method.
• ANSYS shares a white paper on using CFD for simulating an exhaust gas recirculation cooler.
• Stanford University students are using Pointwise, SU2, and Tecplot 360 EX to help design their solar car.
• I seem to recall promising never to post an image of splashed paint again but… what would it look like if you put a Ferrari in a wind tunnel and sprayed it with UV paint? The image below and the ones at the link seem to be a mashup of the best-of and worst-of CFD visualizations.

Fabien Oefner, Ferrari California T. Image from PetaPixel. See link above.

People

• Exa seeks to hire a Senior Software Engineer – CFD Software Development.
• Congratulations to Keith Martin who’s graduating as a Fellow of the Hydro Research Foundation and did CFD research.

Hardware

• I am not a hardware guy, but some people think Soft Machine’s Variable Instruction Set Computing (VISC) could offer great performance improvements.
• NASA’s CFD benchmarks, the NAS Parallel Benchmarks, are used to test the performance of various chipsets.
• Because the Call for Papers deadline has already past all we can do now is wait to read the special issue of Computers and Electrical Engineering on Optimization of Parallel Scientific Applications with Accelerated HPC.
• You can read a little about XFLOW CFD on Rescale’s cloud-based HPC systems.

Congratulations to CEI for the use of EnSight to create the cover image of Nature magazine. Click image for article.

Sculpting via 3D Printing

Artist Moto Waganari wants to create something tangible yet virtual, something solid yet transparent, something that couldn’t be made by hand. His 3D printed sculptures of wireframe humans and other objects are the result. Check out the link for more images and a video.

Moto Waganari, 3D printed sculpture. Image from Visual News.

This reminds me that we at Pointwise need to finalize and release the 3D printing plugin that lets you print your mesh.

Zach Davis, Senior Engineer on the Sales & Marketing team.

I’m on my way to becoming a versatile meshing expert with Pointwise. Structured, unstructured, overset, hybrid…you name it, and I’ll discretize it for you with hexahedra, tetrahedra, pyramids, prisms, etc…all in Pointwise!

I grew up in rural eastern Oregon, studied Aerospace Engineering, and ultimately graduated with an M.S. degree before joining Lockheed Martin’s Skunk Works division in Fort Worth, TX. At Lockheed, I worked on active/passive flow control technology development for applications relating to propulsion integration such as inhibiting boundary layer separation in serpentine inlet ducts and exploring yaw vector control through fluidic injection inside of nozzles. A couple of years later I was transferred within the organization to their Palmdale, CA facility in what I refer to as my classified box in the Mojave Desert where I spent the next eight years doing “stuff.”

In 2010 I moved on to General Atomics Aeronautical Systems in San Diego, CA to provide propulsion integration and CFD expertise for their uninhabited Predator C prototype aircraft before joining Rescale—a startup company in San Francisco, CA whose cloud-based web application caters to engineers and scientists with high performance computing needs. This past April I returned here to Fort Worth, TX to work with Pointwise’s Sales & Marketing team.

• Location: Fort Worth, TX
• Current position: Senior Engineer – Sales & Marketing
• Current computer: Lenovo ThinkPad (Intel i7-3610QM @ 2.30 GHz, 16 GB RAM, NVIDIA Quadro K1000M) with Windows 8.1 & Cygwin
• One word that best describes how you work: Perceptive

What software or tools do you use every day?

I’ve primarily been using Pointwise every day since I hit the ground running this past April in order to hone my skills against a variety of meshing applications and exercise Pointwise’s extensive capabilities. I also use Outlook and Spark for correspondence and collaboration. For my preference towards command line driven interfaces, I’ve installed Cygwin where I can navigate around the file system and network while editing files with vim, sed, and awk. Lastly, I have a program which I wrote, and run in the background, to help me keep track of how much time I have spent towards any given task.

What does your workspace look like?

Zach’s current workspace.

I’ve taken up residence in one of Pointwise’s offices in Fort Worth which has apparently been the office of a few other current and former employees, so it has a lot of history associated with it that I’m still working to uncover. It includes not one, but two windows which is important since I’ve spent the majority of my career thus far in a classified box out in the Mojave Desert. Asides from the windows, it has a pretty substantial bookcase, a corner desk, and two other desks that provide a few different options for where I’m going to sit on any given day.

What are you currently working on? 

I’ve been working diligently towards gaining some proficiency with Pointwise. As a former user of Gridgen and a few other CFD preprocessing related software tools (e.g. GridTool, ICEM, ANSA, Chimera Grid Tools), Pointwise’s learning curve has been by far the most seamless. Part of the reason for this is due to how the entities within Pointwise (i.e. connectors, domains, blocks, etc.) are consistently used throughout the software regardless if you are creating a multi-block structured mesh, overset mesh, unstructured mesh, or hybrid mesh.

The ability within Pointwise to create these various types of meshes and export the results to a wide selection of different solver-specific file formats ensures that diverse engineering teams can effectively collaborate and share their meshing strategies collectively for an assortment of meshing applications. Further, these capabilities provide some insurance that the computational meshes that are expertly created—and the time invested in generating them—aren’t wasted in case an organization opts to change solvers for any number of reasons (e.g. cost, support, etc.). Most preprocessors only support proprietary mesh formats which restrict their use to specific solvers; thereby, limiting their utility.

Here’s a look at some of the meshes I’ve created over the past few weeks with no prior Pointwise experience:

T-Rex grid generated for the LAK-11 sailplane.

Unstructured advancing front surface grid generated on an external automotive geometry.

What would you say is your meshing specialty?

As with several others here at Pointwise, I set out on my professional career with the propulsion integration CFD group at Lockheed Martin’s Aeronautics Company right here in Fort Worth, TX where users primarily used Gridgen for multi-block structured meshes (with both point-matched and non-matching interfaces) in conjunction with Lockheed’s Falcon solver and FieldView. They say your past shapes your future, and I’m definitely more inclined towards creating multi-block structured meshes for their cell count efficiency and prevailing accuracy in comparison to unstructured meshes.

Any tips for our users?

In my short time here I have discovered a wealth of resources that range from case studies, best meshing practices, how-to videos, tutorials, workshops, current events in CFD, and so forth that prospective, new, and experienced Pointwise users can leverage to become more familiar with the software and its comprehensive list of features. I would advocate that users set aside some time to explore the resources available on our website and reference them often as needed. Links to the various resources are listed below for convenience. Be sure to add them to your bookmarks!

• DIY Training Exercises with Video Instruction
• Let’s Talk Meshing Workshop Webinar Archive
• Another Fine Mesh
• Pointwise Documentation
• Glyph Script Exchange
• CFDMeshing on YouTube

Secondly, customers shouldn’t hesitate to reach out to our technical experts here at Pointwise with any specific questions they may have related to their ongoing meshing projects. Let us demonstrate how to accomplish a given task with your specific project in a screen sharing session so you can quickly resolve any issues or have any questions answered pertaining to your current meshing task in real-time.

What project are you most proud of and why?

Given my short tenure at Pointwise thus far, I would probably say I’ve become pretty good at using the keyboard shortcuts within Pointwise and continue to expand my abilities in this regard. Perhaps I could work on an app that quizzes your knowledge of all the Pointwise Accelerators to help customers commit them to memory. It’s all about the little things…

In addition to the other meshes that have already been depicted, I also wrapped a multi-block structured mesh around a louver used for ventilation between walls. This normally would be an extremely tedious structured meshing task, but Pointwise helps expedite building these meshes with its built-in copy, paste, and transform capabilities.

Multiblock structured mesh for a fixed blade louver system.

What CFD solver and postprocessor do you use most often?

I typically use FUN3D and ParaView most frequently. As I mentioned, I used FieldView quite a lot in the past; although, I haven’t had access to a license recently—do we have one lying around somewhere? Anyone?

I also use both SU2 and PyFR solvers on occasion as they continue to mature. Both development teams are active in advancing the state-of-the art in CFD while helping to democratize CFD tools and making them more accessible for everyone.

Are you reading any interesting technical papers we should know about?

I’ve primarily been absorbing everything related to meshing recently which has included some of Dr. Steve Karman’s work with parallelization for large scale Octree mesh generation, Dr. John Steinbrenner’s work on construction of prism and hex layers from anisotropic tetrahedra (both will be presented at AIAA’s 2015 Aviation conference), and John Chawner’s post on Pointwise’s Another Fine Mesh blog titled Accuracy, Convergence and Mesh Quality from a few years ago.

Do you plan on attending any conferences or workshops this year?

I’ll be at AIAA’s Aviation conference from June 21^st through June 26^th with the rest of the Pointwise team, and I’m looking forward to all of the events we have planned for our prospective and current users including the Let’s Talk Meshing session scheduled for Sunday, 21^st June, the reception afterwards, and meeting everyone at our booth Tuesday through Thursday.

What do you do when you’re not generating meshes?

I’ve been a distance runner for almost my entire life, and while I don’t run competitively anymore, I still enjoy getting out and stretching my legs now and again; though, I’m still re-acclimating to the humidity and summer temperatures here in Fort Worth. I also picked up golf as an opportunity to see some sort of greenery while outside of my classified box in the Mojave Desert. It’s grown on me in the years since, and I can definitely appreciate the persistence that professionals of the game must practice to make everything seem simple.

What is some of the best CFD advice you’ve ever received?

Today’s CFD tools are much more streamlined for users than they once were. The underlying models have become a lot more removed, or abstracted away, from new or novice users. Users often run the risk of coupling a poorly crafted mesh with inappropriate solver settings with their simulations. These missteps affect even more experienced users who may be limited in the amount of time they have available for completing an analysis. In either situation, today’s robust generalized flow solvers will likely converge to an answer that may be non-physical or misrepresent the intended flow problem entirely. It’s important that CFD practitioners have a full understanding and complete mastery of the tools that they’re using in order to leverage them correctly and provide meaningful results.

Furthermore, sometimes the 80% answer (a.k.a. back-of-the-envelope or first-order solution) is enough, and expensive simulation isn’t always necessary. It’s invaluable to be well-versed in both the physics relating to the flow problem in addition to the appropriate CFD numerics or best-practices to determine when one is a more favored and valuable approach in any given situation.

If you had to pick a place to have dinner, where would you go?

Either Fogo de Chao or Texas de Brazil would both be at the top of my favorites list which is fortunate now that both are nearby once more.

Travis Carrigan, Senior Engineer on the Sales & Marketing team.

Have you ever been to the Idaho Potato Museum? If not, you should go. They’ll give you a free potato at the end of the tour…or at least they used to. I’ve been there several times. The museum sits in my hometown of Blackfoot, Idaho.

It was back home where I became a pilot and where I spent all my free time bumming around the local airport working on airplanes. Next, I moved to Arlington, Texas where I ended up studying Aerospace Engineering at The University of Texas at Arlington. Before receiving my bachelor’s degree in 2009, I worked as a Quality Assurance Engineer on the Boeing 787 program at Vought Aircraft. The following spring, as I wrapped up my junior year, I was offered an internship at Pointwise on the Technical Support team. I took it immediately.

I spent my first summer at Pointwise working with Carolyn Woeber, the manager of our support team. At the time I was responsible for the functional testing of Gridgen and one of the earlier releases of Pointwise. During the summer I learned enough about grid generation to be productive and knew that I’d be doing CFD from then on.

After receiving my bachelor’s degree I started my second internship at Pointwise, this time on the Sales & Marketing team as an applications engineer working with Chris Sideroff. Chris now distributes and supports our software in Canada. I meshed, and meshed, and meshed, every day, all day, all summer. In just a few months I had generated meshes for geometries in nearly every application area where we have a customer. I was hooked.

I continued working as an intern at Pointwise throughout graduate school. During that time I was working mornings at Pointwise, taking a full course load in the afternoons at UTA, and spending my nights in the CFD lab performing vertical axis wind turbine design optimization. As an intern at that time I helped support the sales process and generated content for webinars, videos, and articles. Most of my original work is still floating around our website.

Just before I wrapped up my master’s degree in Aerospace Engineering at UTA in 2011, I was offered a full time position with Pointwise as a Senior Engineer on the Sales & Marketing team. Since then I’ve been heavily involved in the production of our technical marketing content and sales process.

My primary area of responsibility is new sales. In order to sell our software, I work closely with prospective customers to help strengthen their CFD process by introducing them to Pointwise. Often an engineer will contact us with a meshing problem and it’s my responsibility to determine if Pointwise is the right fit for their application and help them discover the solution throughout a fully supported evaluation. This is a very technical process and one where I’m always learning about new CFD applications and challenges.

• Location: Fort Worth, TX
• Current position: Senior Engineer, Sales & Marketing
• Current computer: Razer Blade, Intel Core i7-4720HQ Quad-Core 2.6GHz, 16GB DDR3 RAM, 512GB SSD, NVIDIA GeForce GTX 970M, QHD+ 3200×1800 pixels, Windows 8.1
• One word that best describes how you work: Wholeheartedly

What software or tools do you use every day?

I live in Outlook. Supporting everyone who is thinking about evaluating Pointwise and those currently working an evaluation means I’m reaching out to potential customers, working with system administrators on installation, fielding technical questions with engineers, and discussing terms and prices with buyers. I work hard to achieve inbox zero by the end of the day because that means I was able to help everyone who reached out to me.

Google Chrome is my window into all our online and web accessible content. I use Chrome to access and manage our Glyph script exchange on GitHub. Throughout the day I’ll look for any Pointwise or meshing questions that arrive via CFD Online. I use TweetDeck to monitor various feeds and tweet events and other CFD related content. Our YouTube page is where we host all our video content and I’m actively uploading new videos and responding to comments. We use YouTrack to log feature requests and bugs in our software, so I keep an eye on that and log any requests that come from discussions with any clients I’m working with. Our internal wiki provides a ton of useful information and is where we work with our developers to define the requirements for new features. I’m currently working on a couple new feature requirements that I can’t wait to share with you! But most of my time spent in Chrome is working with Sage CRM, our customer relationship management software where I track all incoming evaluation requests, quotation requests, and those evaluating the software.

Throughout the day I’ll use Pidgin to chat with my coworkers. A quick message can save a phone call or an email. I use vim when writing or editing Glyph scripts and Cygwin to access my remote Linux workstation to run CFD calculations or generate large meshes. The Microsoft Office suite of tools such as Word, Excel, and PowerPoint, no matter how hard I try to find alternatives, keep me productive. I record a lot of videos including webinars, in-depth meshing videos, and tutorials for #TutorialTuesday. Camtasia makes it easy to capture my screen so I can produce content and get it online quickly. And it goes without saying, but I use Pointwise every single day.

There are two more tools I use that I couldn’t do my job without: GoToMeeting and the phone. GoToMeeting has become such an important part of my job that I can’t imagine working without it. When someone would like to see Pointwise in action, or show me something they’re working on and get feedback, in about a minute I can have a meeting up and running. Often one GoToMeeting session will save an entire day’s worth of email, and I can record it and send it to the client. The phone is similar in that a single phone call can save time, it’s more personal, and allows us to escape the computer for a few minutes.

What does your workspace look like?

Travis’s current workspace.

I’ve moved around our building a lot. I worked in two different conference rooms during my internships, spent a summer in our server room running CFD calculations, worked for about a year in a corner, then an office, and now a corner office. I have a great view of downtown Fort Worth, three large desks, a couple bookshelves, and a plant.

I like to make wherever I’m working comfortable, and by that I mean cluttered with little gizmos and fun stuff. I’ve amassed a small collection of bobble heads against my will and a few really nice aircraft models. Some of the more fun stuff sits on my desk. The Useless Machine provides a lot of entertainment and they have a great return policy—if you don’t find it completely useless, return it for a full refund. Last year I assembled the Strandbeest kit by Gakken and it’s earned a permanent place on my desk. My wife is a Research Scientist at the University of Texas at Arlington’s Research Institute (UTARI) and works in the Biomedical Technologies group. While working on a project involving casting, she made a cast of her hand, which she painted green, and which I stole and proudly display on my desk. I get a kick out of the awkward stares when customers drop by to chat. My wife is very creative and has contributed a number of laser cut wood models to my collection.

What are you currently working on?

A lot of things. I get anxious when I’m not working, so I always have something to do. Most of the work I do is in support of those evaluating Pointwise. I can’t reveal specifics, but what I can say is that during any given week I could be meshing an automotive geometry, a full aircraft, a turbine blade, writing a Glyph script to automate part or all of a meshing process, making a video to demonstrate a particular feature or workflow, or running a CFD calculation to validate a particular meshing strategy. When someone commits to an evaluation, I’m 100% all in to help them discover Pointwise and offer the same level of support they can expect once they become a customer.

Lately I’ve been working on the DrivAer, a realistic external automotive geometry proposed by the Institute of Aerodynamics and Fluid Mechanics at the Technische Universität München. Often automotive geometry is extremely complex, and the DrivAer is no different with over 15,000 unique surfaces. Working with others in this industry I’ve found that a lot of engineers use discrete automotive models (STLs) and meshing algorithms that are tuned for surface wrapping. The difficulty with this approach is that discrete geometry can degrade accuracy and lacks the topological information that analytic models can provide. However, to take advantage of analytic models coming from CAD requires geometry cleanup and robust meshing strategies. Our goal with this project has been to demonstrate such strategies and best practices for cleaning complex analytic CAD often encountered in the automotive industry and automatically generate boundary layer resolved grids. The project has been successful and we’ll be presenting this work coupled with shape deformation and optimization at the 10^th OpenFOAM Workshop.

Hybrid volume mesh for the DrivAer geometry colored by element volume.

I’ve been involved with our webinars and videos since we started producing them back in 2010. I began by producing only the technical content, then drove the software while others presented, and now I organize and produce our webinars with a customer and/or a software partner. Pointwise webinars give people the opportunity to see the software being used in the real world and for many different applications. At the moment I’m working on our next webinar which will go live later this summer. I’m also involved in producing short tutorials in a segment we call #TutorialTuesdays on YouTube and Twitter, along with longer videos that demonstrate the entire meshing process.

What would you say is your meshing specialty?

As I’ve mentioned, one of my roles is pre-sales support during the evaluation stage. Therefore, I must be well versed in our software and best practices so I can help new users get up to speed quickly. That being said, I’d say my meshing specialty is unstructured viscous meshing using T-Rex.

Having worked many different meshing applications over the last few years I’ve come to appreciate the intricacies of getting something rather automated to do what I need it to do for a complex geometry. I know how T-Rex works, I know how and when to apply it, and I know how to get it to do what I want. The secret is all in the surface mesh.

Any tips for our users?

If you’re stuck, contact us. Zach already mentioned it in his post, but I’ll reiterate. Don’t hesitate to contact us if you have a question, comment, or concern. Believe it or not, we love hearing from you. The more feedback the better! We are your grid generation subject matter experts and are available to help in any way we can. Feel free to contact us by phone (1-800-4PTWISE), email (support@pointwise.com), the web, or request a GoToMeeting invitation.

It’s probably scriptable. Glyph scripting is a powerful tool. It gives you access to every command in the Pointwise user interface. However, unlike in the GUI, with Glyph you can string together multiple commands and write your own macros and features. I call this hacking Pointwise since you can get the software to do some pretty incredible things like solving a Rubik’s Cube or playing Pong. A more productive application would involve splitting multiple connectors simultaneously. In Pointwise you would have to split one connector at a time. Another great application is taking a connector, copying, translating, and then stretching it to fit between two points. These three separate tasks can be combined into a single script.

T-Rex is all about the surface mesh. The quality of a volume mesh is highly dependent on the quality of the surface mesh. Keep in mind that when running T-Rex you are advancing elements off of the surface mesh. If your surface mesh quality is poor, the volume mesh will also be poor. So if you encounter a poor quality element in the volume, look at the surface mesh in the vicinity. Not always, but more often than not there is a spacing or something else not set correctly on the surface. Below are my recommendations before generating a volume mesh using T-Rex.

1. Select all the domains on the surface of your geometry (exclude match domains) and examine the area ratio. The area ratio should be less than 4 everywhere. If you find you have a high area ratio, chances are there is a spacing mismatch at a node. When advancing elements off the surface, smaller elements will reach isotropy (T-Rex stop criteria) sooner than larger elements. This means that if you have a large area ratio you have a small element adjacent to a large element and when advancing into the volume mesh the front could stop prematurely.
2. With the surface domains still selected, examine the maximum included angle. Keep this as low as possible. Geometry is going to dictate this, so high angles may not be avoidable all the time. I like to keep my max angle less than 150. If I have an element that’s higher than that I’ll decide whether I need to modify the surface mesh in that region either by joining domains, or by approximating the geometry to eliminate the poor angle.
3. Assuming you haven’t assembled the block yet, take your grid into Grid, Merge and ensure you have no lamina connectors. Lamina connectors on the interior of your grid indicate gaps in the surface mesh and should be fixed or else a watertight volume cannot be generated.

What project are you most proud of and why?

It’s a tie between two Glyph scripting projects. I began working on the first project just before I was hired full time. It was a project for a Quiet Aircraft Technology program member and I worked with Nick Wyman to automate the meshing for conical and chevron jet nozzles. The Glyph scripts we wrote automatically generated overset, multiblock structured grids given an input nozzle geometry. We developed a user interface for each script that exposed all the meshing parameters necessary to generate the grids from scratch so the end-user wouldn’t have to load up the Pointwise GUI. Once the grid had been generated, the script would export all the component grids and PEGASUS control file used for the overset grid assembly. Acoustic simulations were performed, requiring the grids to be of very high quality. To give you an idea how much time this saved the engineers, assembling a single grid by hand would take one to three days depending on the complexity of the nozzle. The script reduced that to under an hour.

Graphical user interface for the jet nozzle overset meshing Glyph script.

The second project was a Glyph scripting library I wrote to elevate the order of linear elements generated using Pointwise. Using the grid coordinate enumerator written in Glyph by David Garlisch, a Senior Engineer on our Product Development team, I was able to gain access to the grid model, compute the nodal locations for the additional points including placing them on the CAD geometry where appropriate, and generate the higher order connectivity for each element. The script was successfully coupled with a script generated by Cameron, Compression Systems that automatically generated multiblock structured finite element grids for open-faced centrifugal impellers. In the end we had a set of automated tools for generating higher order hexahedral grids to improve the prediction of centrifugal impeller failure modes.

The inducer view of the centrifugal impeller illustrates the use of quadratic hexahedral elements. This mesh was generated automatically.

What CFD solver and postprocessor do you use most often?

When I need to validate a meshing strategy for a particular application or when I’m working on a project that requires I run a calculation, I rely on a few open source CFD solvers. I’m primarily using OpenFOAM on my Linux workstation for incompressible, steady and unsteady simulations. I’ve been using OpenFOAM for more than five years now and worked with David Garlisch to develop a plugin so Pointwise users can seamlessly export a grid to OpenFOAM without the need to run any additional meshing utilities.

Recently I’ve been using Caelus, a restructured derivative of OpenFOAM that runs on my Windows machine. Because it was forked from OpenFOAM, it’s an environment I’m comfortable working in. That being said, under the covers Caelus is different. Solvers are only included if they’ve been validated against published data, the turbulence models and wall functions have been rewritten, and a number of library enhancements have been made including updated interpolation and gradient schemes.

I’m also using SU2, an open source CFD solver developed out of Stanford University. I have SU2 running on both my Windows machine and my Linux workstation and primarily use it for external aerodynamics calculations. Over the past couple years we’ve done a lot of work with the SU2 team. Last year we hosted a webinar and discussed supersonic aircraft shape design using the Lockheed Martin 1021, a test case from the AIAA Sonic Boom Prediction Workshop. As part of the project I wrote a Glyph script to generate free form deformation boxes and export the data to SU2 for shape deformation. A few months later we held a joint workshop at Stanford where we walked through the entire CFD process using Pointwise and SU2.

For postprocessing I use a mix of ParaView, EnSight by CEI, and Tecplot. My OpenFOAM environment is setup to load results directly into ParaView, and I’m using both EnSight and Tecplot for grid visualization and solution visualization. Our first joint webinar was hosted by Tecplot and we discussed an automated methodology for optimizing the aerodynamic performance of vertical axis wind turbine rotors, my master’s work. We’ve hosted a couple webinars with CEI. One involved North American Eagle and an attempt to break the land speed record, another with CRAFT Tech and analysis of cavitation and acoustics of a water injection pump.

Are you reading any interesting technical papers we should know about?

A few. I’m reading John Steinbrenner’s Construction of Prism and Hex Layers from Anisotropic Tetrahedra which describes T-Rex and more specifically the evolution of cell combination techniques. I’m also reading Aeroacoustic Simulations of a Nose Landing Gear using FUN3D on Pointwise Unstructured Grids by V.N. Vatsa, M.R. Khorrami, J. Rhoads, and D.P. Lockard. Both papers will be presented at AIAA Aviation. While working on the DrivAer grids and simulations I’ve been reading Experimental and Numerical Investigation of the DrivAer Model by A.I. Heft, T. Indinger, and N.A. Adams.

Recently I had the opportunity to attend one of Edward Tufte’s courses on Presenting Data and Information. John Chawner recently wrote an article describing a few of the highlights. After taking the course I started reading Beautiful Evidence. It’s a great book and I especially enjoyed the chapters on sparklines and the fundamental principles of analytical design.

Do you plan on attending any conferences or workshops this year?

Absolutely! This month alone I’ll be at three different conferences and workshops. June 15^th-19^th I’ll be in Montreal at TurboExpo. Please drop by the booth and we can chat about your turbomachinery meshing applications. The following week I’ll be at AIAA Aviation. Be sure to attend our Let’s Talk Meshing Workshop on June 21^st before the conference. You’ll learn how to use our latest overset meshing tools, get an introduction to Suggar++, see some new Pointwise features, I’ll be teaching you how to get started with Glyph scripting, and our president will present the product roadmap for Pointwise. You won’t want to miss it. The week after Aviation I’ll be in Ann Arbor, Michigan at the 10^th OpenFOAM Workshop. There I’ll be presenting our work on the DrivAer automotive model. Come by and I’ll show you how Pointwise seamlessly integrates with OpenFOAM. The last week of July I’ll be in Orlando, Florida at the AIAA Propulsion and Energy conference.

What do you do when you’re not generating meshes?

Sleep.

Just kidding. I have a lot of different hobbies from running CFD on a Raspberry Pi to building a home flight simulator. After graduate school I started reading again and am a big fan of Daniel Suarez and his books. Right now I’m reading Beautiful Evidence by Edward Tufte, To Sell Is Human by Daniel H. Pink, The Everything Store by Brad Stone, and IT by Stephen King.

I do a lot of gaming on iOS, Android, PC, and the PS4. A few years ago I fell into indie gaming and discovered a unique world of art I never knew existed. I could recommend a dozen or more great indie titles, but anything by Amanita Design is absolutely perfect. Samorost, Machinarium, and Botanicula will leave you speechless.

Something else I discovered by chance was coffee. Those who know me know I’m coffee crazy. I’ve amassed a collection of more than ten different coffee makers, all manual brewers with different filtering mechanics. I could go on all day about coffee and the science and art of brewing but I won’t. Instead all I’ll tell you is that real coffee doesn’t taste like Starbucks or a K-cup. A real cup of coffee brewed properly will highlight flavors you never knew existed. Imagine drinking a cup of coffee so sweet that you don’t need to add sugar and so smooth that milk and cream are no longer necessary. The Hario V60 is the most natural way to brew a cup of coffee and gives you control of the brew ratio, grind size, water temperature, bloom time, and brew time. If you want to learn more you can visit my blog. Unfortunately it hasn’t been updated in a while, but there’s plenty of great content.

Few of my hobbies would be fun without someone to share them with. My wife’s a great sport and supportive of everything I do. The two of us do everything together and have recently taken up fishing near our home. She’s a phenomenal cook, a great travel companion, and my best friend. When I’m not generating meshes I’m spending time with her, sipping a coffee and relaxing.

What is some of the best CFD advice you’ve ever received?

“All models are wrong, but some are useful.” –George E. P. Box

If you had to pick a place to have dinner, where would you go?

My wife and I love to eat and try new restaurants wherever we go. Here in Fort Worth, Texas I would recommend Rodeo Goat for the best burger in DFW. If I were back home in Blackfoot, Idaho it would be Rupes. Be sure to try the fry sauce. In San Antonio, Texas I’d say Boudro’s on the Riverwalk. Seattle, Washington would be Elliott’s Oyster House, probably the best seafood place I’ve been to. In San Jose, California you’ve got to drop by Pizza Antica on Santana Row and when you’re finished walk across the street to the Tesla shop just for fun. In New York City definitely Xi’an Famous Foods for some authentic Chinese. If you’re in Albany, New York be sure to try Dave’s Gourmet & Exotic Burgers. It’s the only burger place I know of that sells a python, camel, and kangaroo burger. And lastly, when in Montreal you must visit Le Gourmand Restaurant.

During this past October, I had the pleasure of joining the Pointwise team on a trip to Japan for the 2015 VINAS User Group Meeting. VINAS (Visual Integration & Numerical Analysis Systems) is a Japanese company specializing in the distribution and support of numerous CAE and CFD products, including the Pointwise meshing software. At the conference, I was invited to present our open-source SU2 suite for CFD analysis and design (https://github.com/su2code), which was a great opportunity to reach a new audience.

The trip began in Osaka and ended in Tokyo. In between, I tried to maximize my interactions with Japanese food, culture, and of course, the people. Only an engineer would think of a trip like this as an optimization problem.

Getting Started in Osaka and Kyoto

Before leaving the US, many people encouraged me to explore and enjoy the food. Having been raised in the middle of the US away from the coasts, I was not well-versed in the seafood-heavy fare that I was about to find in Japan. However, upon arrival, I planned to completely immerse myself in the food. This meant two things:

1. I had to up my chopstick game quickly.
2. I wanted to tackle anything made available to me, including so called “challenge” foods for westerners.

I had an easy warmup with the chopsticks on some gyoza, which were relatively easy to grip with the sticks. Within a few hours, I was “immersing myself” into some fresh octopus. By the end of the week, I had sampled many of the well-known dishes: fresh sushi of all sorts, ramen, udon, tonkatsu, unagi, shabu shabu, and others. I’ll be having more Japanese food locally now with hopes of recapturing the magic and keeping up my chopstick skills.

A beautiful example of the high quality presentation that you can see in Japanese meals.

The dining experience brings out the amazing attention to detail that I encountered throughout Japanese culture. Presentation and ceremony play leading roles right alongside taste. Meals typically arrive in many small portions, each having its own vessel with distinct decoration and purpose. Shared dishes and rituals, such as refilling your neighbor’s glass when empty, really enhanced group dining.

One recurring trend that I had read about beforehand, but couldn’t quite appreciate until I experienced it, was the blending of old and new culture in Japan. I was repeatedly (and pleasantly) surprised when our group would fight through traffic or crowds on busy city streets only to have the entire hustle and bustle peel away within steps to leave us in an ancient shrine or temple. It was interesting to learn that more emphasis is placed on the location of the temple/shrine rather than on man-made structures or buildings sitting on it, which often come down and are rebuilt over time. As one might expect, these sites specialize in peaceful atmosphere and natural beauty.

Visiting Kinkaku-ji (Temple of the Golden Pavilion) in Kyoto.

Other impressions from the Osaka / Kyoto area:

• I enjoyed the mythology behind the temples and shrines. Themes emerged around doors / paths / choices, fortunes or wish granting, and dedicating sacred places after specific actions, often tied to animals.
• Vertical space is leveraged more and differently than in the US. Buildings often unfold like labyrinths in unexpected ways with different levels.
• History and landmarks are old on a scale that we don’t often encounter in the US. For instance, the 400th anniversary of the war between the Toyotomi and Tokugawa clans was being recognized during our visit to Osaka Castle.

The first portion of the journey came to a close with a high-speed train ride to Tokyo on the Shinkansen line. Naturally, I went to the front of the train immediately and thought about how I would set up the aerodynamic shape optimization problem in SU2 for designing the outer mold line of the train’s nose and body.

The nose of a bullet train on the Shinkansen line.

Visiting JAXA Chofu

After arriving in Tokyo, but before the start of the conference, we made a visit to the JAXA (Japan Aerospace Exploration Agency, http://global.jaxa.jp) Chofu research center, where the focus is on research and technology for aviation. During this visit, we met with the current developers of FaSTAR, an unstructured CFD code created at JAXA. We exchanged presentations on our strategies for solver development as well as our current and future directions.

While FaSTAR and SU2 contain quite a few similar features and methods, we have differing approaches in our development. SU2 is an open-source code, while FaSTAR is not, and this has important implications for our priorities as developers.

For example, our philosophies differ when it comes to flexibility and performance. In SU2, we deliberately favor in-house solutions over external libraries (when we can) and leverage object-oriented programming in C++ so that the code is easy for the community to understand, compile on many architectures, and modify. This is typically at odds with performance, and as a result, we have put in extra effort as a development team to maintain high performance with SU2. In contrast, the FaSTAR team has prioritized speed above all else. In that regard, they have achieved some impressive results in reducing the time-to-solution of Reynolds-averaged Navier-Stokes (RANS) calculations around realistic applications down to minutes on their latest supercomputing hardware (for engineering accuracy).

Inside the JAXA visitor center with Yasuhiko Fujikawa (VINAS, left) and Rick Matus (Pointwise, right).

We also discussed high-performance computing (HPC) in general and our strategies for attaining scalable, high performance with the codes. Topics included emerging hardware architectures, how new architectures are affecting their parallel programming models, and where they see things going in Japan given recent upgrades to their HPC system (JSS2).

Similar to the current trend in the US, they are pursuing hybrid programming models to unlock the multiple levels of parallelism on emerging systems. We are both investigating the so-called “MPI + X” model, where MPI is used for coarse-grain parallelism across distributed memory systems while something else (the “X”) is used to achieve fine-grain parallelism within a single compute node (threading and/or SIMD).

Having spent some time at our NASA centers in the US, I should also mention that I felt very at home on the JAXA Chofu campus. If I squinted hard enough, I could imagine it as NASA Langley or Ames given the similar layout and style to the buildings.

VINAS UGM in Tokyo

The 2015 VINAS Users Conference was held in the Tokyo Conference Center Shinagawa. The overall themes of the conference were open-source CFD solvers (Day 1), pre- and post-processing for CFD (Day 1), turbomachinery design and optimization (Day 2), and HPC cloud computing and high speed calculation (Day 2). I was very impressed with the professionalism with which the conference was executed, from the live translation of talks from English to Japanese, all the way down to the subtle touches like special lighting during the introduction of speakers.

Intelligent Light’s Yves-Marie Lefebvre showed off some features from the new FieldView version 16 (http://www.ilight.com/en/products/fieldview-16) early in the day. Two items that particularly intrigued me are their ability to export into 3D PDF format and their free XDBview software. It was my first exposure to 3D PDF, and it looks to be particularly useful when sharing and communicating results for CFD. Sometimes a quick pan and/or rotate around a 3D solution gets the message across when a series of flat images and words are failing (or, at best, taking much longer). I also noted that Boeing is part of the consortium of companies supporting the development and growth of 3D PDF.

A partial shot of the VINAS UGM agenda for Day 1.

Rick Matus from Pointwise teased a number of features from the upcoming version 18 of their flagship software product along with several examples of the meshing package at work. As a developer of an unstructured CFD solver, I eagerly await the unstructured quad or quad dominant surface meshing coming in Pointwise V18. Couple that with T-Rex for automatically generating boundary layer-resolving meshes, and you might just get the best of both worlds: hex cells for accuracy where you need it most while maintaining efficient unstructured mesh construction around complex geometries.

Open-source software played a prominent role in the first day of the conference. After giving an overview of how the open-source SU2 suite can be used for CFD analysis and design optimization, I listened intently to back-to-back presentations by ENGYS’ Paulo Geremia on the HELYX software suite. HELYX is package for CFD design and optimization that is built around the open-source OpenFOAM library (http://engys.com/products/helyx). The presence of efficient adjoint-based methods for gradient-based optimization within HELYX (similar to methods we develop and apply within SU2) was particularly noteworthy for me.

Presenting the open-source SU2 suite and several design applications at the VINAS UGM 2015.

Talks by Torbjörn Larsson and Pierre-Jean Tardy offered an insider’s look at the cutting-edge engineering work within the Formula 1 industry. Strict F1 rules and regulations dictate how teams spend their time and energy in search of performance improvements. I have often heard about the heavy use of CFD throughout the sport, but the integration of CFD into their design processes went much deeper than I expected.

The full program for the VINAS Users Conference can be found here: http://www.vinas.com/en/ugm2015/program_day1.html.

Elsewhere in the Tokyo Area

Despite its large size and high population density (or perhaps made necessary because of it), Tokyo exhibits serious efficiency in its operation. You can sense the ebb and flow all around you in the sounds of hundreds of footsteps in the corridor of the train station or the sight of hundreds of people queueing up near the massive crosswalks (Shibuya Crossing being the most obvious example). The train system was impressive, and its vast web makes it easy to get just about anywhere around Tokyo with the combination of a train ride and a short walk. By the end of the week, even a foreigner like myself had a decent grip on the different lines and stations and felt comfortable getting around town.

By the way, the citizens of Tokyo take the commute mentioned above in style. Everywhere I looked, I saw well-tailored suits and dresses, stylish jackets and sweaters, and eye-catching accessories. This was yet another example of the attention to detail that I found throughout Japan.

A few additional items that struck me in and around Tokyo:

• The vast open spaces surrounding the Imperial Palace, including patches of grass so fine and bright that they looked like a layer of green fog covering the ground.
• The architecture of the buildings in the Ginza shopping district. It feels like the buildings themselves are competing to be noticed by including unique design elements, such as the irregular window pattern on the Mikimoto building.
• The fascinating array of seafood on display at the Tsukiji fish market in all manner of colors, shapes, and sizes.

Conclusion

Overall, this trip had a little bit of everything, including unforgettable food, sights, and excellent technical content. I left with a great impression of Japan and its friendly people, and I am looking forward to my next visit.

I enjoyed meeting many new folks in the solver and visualization industries, and I hope that I have passed along some of our enthusiasm for open-source solvers through my presentation on SU2.

Lastly, I would like to thank Yasuhiko Fujikawa and his entire team at VINAS for being wonderful hosts and Heather McCoy, Rick Matus, and Carolyn Woeber from Pointwise for all of their time and energy spent showing me their favorite places in Japan and making me feel at home in a new place.

Disclaimer: The opinions above are entirely my own and not those of VINAS or Pointwise. I would also like to note that my travel expenses for attending the conference were generously covered by both companies. 

Dr. Thomas D. Economon is a Postdoctoral Scholar at Stanford University, where he received MS and PhD degrees in the Department of Aeronautics & Astronautics. He holds a BS in Aerospace Engineering from the University of Notre Dame. His research interests include computational fluid dynamics, optimal shape design via adjoint-based methods, and high performance computing. He serves as the co-lead developer of the open-source SU2 CFD suite.