There’s a practical way to define convergence of a CFD solution. It’s when you run out of time or budget or both. That’s what happened with this edition of This Week in CFD after a 56 day hiatus. I ran out of time before I had exhausted my backlog of bookmarked CFD news. Like yesterday’s Thanksgiving turkey, this edition is stuffed and you’ll be getting the leftovers next Friday. But enough blather. 

In the beginning…

• The Congress on the Future of Engineering Software (COFES) 2019 is coming up in April next year and will be held in Menlo Park, California for a change of scenery (after many years in Scottsdale, AZ).
• CFD is being used in the design of the MQ-25 unmanned, carrier-capable, inflight refueling aircraft.
• Here are some movie making tips for engineers. [No, not the next big screen epic.] Altair’s blog shares tips from Intelligent Light on making movies of your CFD results.
• Resolved Analytics is running a CFD Software User Survey to find out “what, why, and how [you] use CFD software.” And you might win an Amazon gift card.
• Speaking of Resolved Analytics, their series on Comparing CFD Software is being published online.
  • Part 1, CAD Embedded CFD
  • Part 2, Open Source CFD Software Packages
  • Part 3, Semi-Comprehensive and Specialty CFD Software Packages (coming soon)
• MY FAVORITE CFD application of the week: CFD was used in a study to show that fishing hook damage to a fish’s mouth could be sufficient to kill it due to a degraded ability to feed itself. So next time you haul in Nemo, it might be better for him if you take him home for dinner instead of tossing him back.
• An article about Haas F-1, Cray, and CFD.

An image from OceanMesh2D 1.0, a MATLAB-based mesher for coastal modeling showing cells colored by circumradius in meters around Puerto Rico and the U.S. Virgin Islands. Image from a full technical paper hosted at geosci-model-dev-discuss.net. Click link for full paper.

Museum Quality Meshes

My good friend Kelly has made a joke about meshes belonging in a museum. Regardless, during his presentation at the Pointwise User Group Meeting 2018, Dr. Bruce Hilbert shared work he’s involved in at Branch Technology where they 3-D printed (from a plant-based plastic) a hanging garden for installation in Chicago’s Field Museum.

Hanging gardens are a part of the Griffin Dinosaur Experience in Chicago’s Field Museum. Image from fieldmuseum.org. See link above.

If you look closely you’ll see the structures are 3-D printed meshes and that are a product of Branch Technology‘s secret sauce. [Personally, this is one of the coolest applications of meshing I have ever seen.]

Close-up of the 3-D printed structures fabricated by Branch Technology. Image from branch.technology. See link above.

“All good writing is swimming underwater and holding your breath.” F. Scott Fitzgerald

Which explains why I’m drowning.

• OpenMesh is a “generic and efficient data structure for representing and manipulating polygonal meshes.”
• HexaLab is a free-to-use, online, mesh visualizer.
• Thingi10K is a study of all 3-D printing models on Thingiverse.
• When the Wall Street Journal says that rainbow color maps impede understanding (in the context of weather maps) maybe it’s time we in CFD ought to heed that advice too. [That’s one reason why we added Viridis and Plasma color maps to mesh metric evaluation in Pointwise.]
• Speaking of colormaps, Tecplot 360 2018 Release 2 is out and includes – guess what – 19 new colormaps with Viridis as the default.
• Microsoft has put the source code for MS-DOS 2.0 on GitHub for all to enjoy.
• Here’s a 50-page (including best practices and  11+ pages of references) on RANS versus LES for simulating flow over the exterior of buildings.
• The folks from Ingrid Cloud build upon market research by the Aberdeen Group to show that CFD’s ROI continues to grow.
• Speaking of the cloud, Altair’s tools are now available through Oracle’s cloud.
• OpenFOAM is the basis for a new CFD capability being developed for exhaust dispersion simulations of flues and chimneys.
• This is from 2015 but it’s new to me: a technique called Instant Meshes that seems to very quickly convert a dense surface mesh of triangles into either a coarse triangle or quad surface mesh that’s aligned with features.
• COMSOL Multiphysics v5.4 was released with a compiler that let’s you write standalone apps.
  • Here’s more on that from DEVELOP3D.

A ParaView plugin for visualizing high-order data. Image from perso.uclouvain.be/sebastien.blaise.

“Nothing stinks like a pile of unpublished writing.” Sylvia Plath

That may explain the odor coming from my Chrome bookmarks.

• Monica Schnitger wrote the first report I saw of Altair’s acquisition of SIMSOLID.
• Attention students: NASA’s University Aeronautics Design Challenge 2018-2019 seeks designs on paper for a self-piloted aircraft for critical rural/suburban needs. Looks like the deadline was extended to 15 June 2019 but you have to let them know you’re participating by 15 February.
• While we’re on the topic of students, this blog post from ANSYS advocates for teaching the basics of FEA and/or CFD to undergraduates. At the risk of being perceived as a software shill, I won’t disagree. However, there’s a fine line between learning the basics of simulation versus learning how to run specific simulation tools. IMO, an undergraduate engineering education is not a trade school. [I’ve respectfully disagreed with some of my colleagues from bigger companies on this topic. If you want students to emerge from school knowing how to push the buttons for software “X” that’s exactly and all you’ll get.]
• Read how Aerion is using Tecplot Chorus to evaluate CFD results for their supersonic business jet.
• I wasn’t even aware of the Advania HPCFLOW Cloud until I read this case study.
• ElVis is a visualization system for high-order FEA solutions.
• Hexagon acquired Bricsys, makers of the BricsCAD software.

Propeller vortices as computed by NUMECA, from an article about meshing topologies for bulbs. Image from numeca.com.

“The art of writing is the art of discovering what you believe.” Gustave Flaubert

I believe I’ve compiled a backlog of way too much CFD news.

• A Crash Course for SU2 Hackers from their 3rd annual developers meeting encourages you to “try crazy things.”
• I HIGHLY RECOMMEND this article from an architecture blog: On the Spline: A Brief History of the Computational Curve, especially for my friends from the CFD side of the aisle (versus the meshing side). [Of special note is the role my alma mater, Syracuse University, played in the development of this technology.]
• Speaking of geometry, Engineering.com writes about CADfix 12 where the goal is “making models more meshable.” [Bonus points for alliteration.]
• This is slightly off-topic but an article claims that in the 2000s the design of the SR-71 was run through sophisticated aircraft design software and the result validated 100% every design choice made by those engineers back in the 50s and 60s. While I agree that the Blackbird is a marvel of engineering and a tribute to the men and women who brought her to life, I’d like to know a bit more about what kind of software validated its design and how.
• Siemens PLM released Femap version 12.
• New to me, the Azore CFD solver. [I wonder if it runs on Azure. Had to be asked.]
• I love discovering new CFD software – FlowVision.
• And more: Flow360 which claims to be able to compute a 50 million grid point solution in “minutes” or in a tiny fraction of the time of other commercial CFD solvers. [Note: Their website shows a mesh from Pointwise that they harvested off teh interwebs but we have yet to have any substantial dialog with them about compatibility.]
• CFD as applied to offshore, floating, renewable energy devices.

This is kinda how my head feels after generating meshes for too long. [And by too long I mean over 30 years.] This image is one of many from a post on Colossal about the work of Marcus Martinez. Image from Colossal.

“The greatest pleasure of writing is not what it’s about but the inner music that the words make.” Truman Capote

All I hear is a cacophony.

• The title got my attention but my decaying technical skills left me unable to grok the contents. Maybe one of you can help me understand Decoupling Simulation Accuracy from Mesh Quality.
• Mesh2Surface version 5, a Rhino plugin that converts scan data to CAD models, is now available.
• Another HIGHLY RECOMMENDED read: The CAD Interoperability Survival Guide from Tech-Clarity.
• From Aerospace Manufacturing and Design comes an article about the use of CFD in a multidisciplinary environment to study wing designs for fuel efficiency. [In which we read that airliners of today use 80% less fuel that those of the 1950s.]
• I think there’s been an update to CFDTool, the MATLAB CFD Toolbox, but I can’t find a notice so I’ll just link to their website.
• Use of CFD to design efficient marine propulsion systems.
• Ditto.
• And on the same topic, an effort to develop a benchmark for ship energy efficiency seeks participants.
• 3DX is a website for exchange of 3-D models.
• CFD and 3-D printing were used to customize a triathlete’s racing bike‘s “aero cockpit.”

Screen capture from a video on skyscrapers, wind loads, and CFD featuring SimScale.

“Writing is simply thinking through my fingers.” Isaac Asimov

My fingers aren’t very bright.

• As you are probably aware, NASA has been celebrating their 60th anniversary. Here’s their video, 60 years in 60 seconds.
• Speaking of NASA, 2019 is the 50th anniversary of Apollo 11’s landing on the moon. Be ready for all the moon stuff you can handle next year. Buzz Aldrin already has his Road to Apollo 11 50th Anniversary site up.
• Detroit Engineered Products has been granted a U.S. patent for its CAD morphing technology.
• Speaking of morphing, Skintite is a product for both converting scan data to CAD models and morphing CAD models.
• Use of CFD to design a Camaro Supercar.
• CFD, machine learning, and the human heart.
• I think I’ve found the first two parts of a series from Digital Engineering on simulation for beginners.
  • A Beginner’s Guide to Simulation, Part 1
  • Transition to Simulation Via Training, Part 2
• The topic of ITAR-controlled data (ITAR is a U.S. regulation that restricts the export of certain things) is important on its own but the cloud raises that importance to a very high and very practical level. Read more in ITAR Compliance in the Age of On-Demand HPC. [In my experience, a fundamental threat to violations of the ITAR (international traffic in arms regulations) is the simple fact that many data owners don’t know themselves whether or not their data is subject to it.]

Andy Gilmore, title unknown. Image from the artist’s website.

“Easy reading is damn hard writing.” Nathaniel Hawthorne

Unfortunately for you, I’ve chosen the opposite path.

• Ars Technica writes about the oldest, unsolved problem in physics: turbulence.
• HPC Wire wrote a short piece about the use of OpenFOAM.
• OpenQBBM 4.0.0 is now available for quadrature-based moment methods.
• Speaking of open-source, here’s a first-hand account of contributing research to an open-source project.
• Siemens PLM seek to hire a Software Engineer – Advanced – Meshing at multiple locations.
• Speaking of jobs, Pointwise has an open Sales Representative position on our Tech Sales team in Fort Worth.
• B-Splines I know. T-Splines I’m aware of. But now I’m way behind on U-Splines.
• The 3MF consortium is developing a standard file format for 3-D printing that should be an improvement over STL.
• TotalSim is opening the Silverstone Sports Engineering Hub for the cycling industry with wind tunnels, scanners, and CFD. Here’s more from a different publication.
• The Society of Marine Architects and Naval Engineers (SNAME) Maritime Convention 2019 will be held 29 Oct – 02 Nov in Tacoma, WA.
• Why engineering graphics matter more now than ever.
• Data storage and backups in F-1.
• ANSYS now has an App Store. [Which I would’ve branded as AppSYS but what do I know.]
• Nektar++ v4.4.0 has been released. (It’s a spectral/HP element framework and I do like their logo.)

When a meteorologist is also a baseball fan you know that using CFD to study the weather’s effect on the distance a hit ball will fly isn’t too far behind. Image from Forbes.com.

Generate Meshes, Generate Art

In an article about generative art (art created using a computer using various techniques including “controlled randomness”), Jason Bailey on Artnome sees a lineage all the way back to Cezanne.

Given that I’ve spent over three decades generating meshes, the name generative art alone gives the Walter Mitty in me just a bit of optimism that maybe – just maybe – I could do this too. Plus, with the topic of generative design arising more and more frequently in CAE circles, another parallel of art and science warms my heart.

So it brought a smile to my face to learn that one of the earliest examples of generative art is decidedly mesh-like, Georg Nees’ Gravel (see below). This works makes me think “I could do that,” a slippery slope because while our software provides the mechanism to draw something like that, the forethought to decide to attempt it and the visual skill to decide where and how to introduce the randomness likely escapes me.

Georg Nees, Schotter (Gravel), 1968. See link above.