This Week in CFD

Software

  • CAESES 4.1.2 was released. This new version of Friendship Systems’ modeling and optimization software with improved adjoint CFD coupling and more.
  • ESI announced VA One 2016, the latest release of their modeling environment for noise and vibration simulations. (See image below.)
  • ENGYS released HELYX V2.5.0.
  • simFlow 3.0, an OpenFOAM-based CFD solver, was released and includes an airfoil mesh generator among other new features.
  • MSC Software announced a new release (Fossa) of Apex, their next-generation CAE platform with Python scripting. [I’m intrigued by the definitions of “fossa” that I’m finding online. A civet-like mammal. A shallow depression.]
  • Materialise announced the beta test program for Magics21, the core component of their 3D printing software suite, for editing faceted geometry models.
  • ITI launched CADfix 11, their software for CAD model translation, repair, and simplification. This latest release includes geometry morphing capabilities among many other new and updated features.
  • Vectary, the new 3D online modeling tool, is currently in beta.
  • The availability of Autodesk’s technology preview of Project Calrissian for CFD has been extended through 25 November.
The new Diamondback triathalon bike screams aerodynamics and whispers CFD. Image from BikeRadar.com. Click image for article.

The new Diamondback triathlon bike screams aerodynamics and whispers CFD. Image from BikeRadar.com. Click image for article.

Applications & Events

Amazing indeed. CFD solves mazes. Image from Symscape. Click image for article. (Now if it could only help me solve the Sudoku.)

Amazing indeed. CFD solves mazes. Image from Symscape. Click image for article. (If CFD could only help me solve the Sudoku.)

  • Processing Magazine delves into CFD for mixer design. It requires “sound volume-meshing techniques.”
  • CD-adapco is partnering with Spike Aerospace on design of a supersonic business jet.
  • Prof. Brian Spalding was announced as a keynote lecturer (“The Shape of CFDs to Come”) at next month’s 4th Annual OpenFOAM User Conference 2016.
Example mesh and simulation from FloEFD for LED automotive headlights. Image from Engineering.com. Click image for article.

Example mesh and simulation from FloEFD for LED automotive headlights. Image from Engineering.com. Click image for article.

Computing & News

  • Exascale computing is proving to be difficult, even on the hardware side.
  • ANSYS and SGI claimed an HPC record for CFD by running an 830 million cell simulation of a gas combustor in ANSYS 17 on an SGI ICE XA using 145,152 compute cores with 83% efficiency.
    • Also from ANSYS, they reported Q2 revenue of $246 million.
  • Read about the Exascale Computing Project from the U.S. Dept. of Energy.
  • Market analysts TechNavio are predicting a global CFD market in 2020 of US$1.8 billion, with an annual growth rate of 9% from now until then.
Read about what's new in SolidWorks Simulation 2017 including meshing improvements. Image from EngineersRule.com. Click image for article.

Read about what’s new in SolidWorks Simulation 2017 including meshing improvements. Image from EngineersRule.com. Click image for article.

Visualization & More

Fluctuating surface pressure from an automotive simulation using OpenFOAM. This beautiful image is from ESI. See link above.

Fluctuating surface pressure from an automotive simulation using OpenFOAM. This beautiful image is from ESI. See link above.

Winner of The Meshy Award for 2016

The winner of The Meshy Award was announced yesterday at the Pointwise User Group Meeting 2016. From a broad spectrum of well-qualified entries (see the photo album on our Facebook page) the judges selected a truly innovative use of mesh generation technology from Branch Technology. The company is using Pointwise to generate meshes that are 3D printed on an architectural scale for use in construction. Their winning entry is for the Cheekwood International Playhouse. Congratulations to C. Bruce Hilbert and Melody Reese from Branch Tech.

The winning mesh for The Meshy Award, announced at the Pointwise User Group Meeting 2016, was Branch Technologies 3D printed mesh.

The winning mesh for The Meshy Award, announced at the Pointwise User Group Meeting 2016, was Branch Technologies 3D printed mesh.

Posted in Applications, Events, Hardware, News, Software | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

This Is How I Glyph – Dimension Connectors From Spacings

68747470733a2f2f7261772e6769746875622e636f6d2f706f696e74776973652f44696d656e73696f6e436f6e46726f6d53706163696e67732f6d61737465722f536372697074496d6167652e504e47

When using 2-D T-Rex in Pointwise to resolve highly curved surfaces with anisotropic triangles—the leading edge of a wing section for example—it’s usually recommended to keep the aspect ratio of these anisotropic triangles within some limit.  We recommend an aspect ratio between 10 and 20 for most applications.  To control the aspect ratio, either the initial spacing used by 2-D T-Rex can be changed, or the spacing between grid points along the wall type connectors can be adjusted.  There are a few different ways to arrive at such a distribution of points along these connectors in Pointwise.  The DimensionConFromSpacings.glf Glyph script provides one way to help users arrive at just such a distribution of grid points using the default hyperbolic tangent distribution type along a set of connectors.

The DimensionConFromSpacings.glf Glyph script provides users with a Tk based interface with entry fields where users can specify beginning and ending spacing values in addition to a maximum allowable spacing between grid points for a set of connectors.  Users first select connectors that they wish to dimension, provide requisite spacing parameters, and the script uses this information in conjunction with the length of each connector to iterate upon the number of grid points that meets the prescribed spacing constraints.  Once determined, each connector is dimensioned with the beginning and ending spacing parameters applied accordingly.  Users can also acquire the initial, ending, and max grid point spacing values from existing dimensioned connectors to use in dimensioning new connectors using the same set of parameters.

The DimensionConFromSpacings.glf is available at the project’s repository hosted on GitHub.  You can use this link to download the script directly.

If you have an idea for a new Glyph script, and you would like to learn more about how to get started, then contact us via the comments section below or contact @Pointwise on Twitter.  We’re also interested in learning more about the Glyph scripts our users have created.  Get in touch with us if you would like to share and have your script highlighted here on Another Fine Mesh.

Posted in Applications | Tagged , , , , , , , , | Leave a comment

I’m Chavaly Venkatesh and This Is How I Mesh

Chavaly Venkatesh, Partner, KFour Metrics.

Chavaly Venkatesh, Partner, KFour Metrics.

An impartial absence of malice towards any subject that didn’t involve formalin meant I could pretty much play the field on leaving school. The dice were rolled, and I found myself working towards a Bachelor’s degree in Mechanical Engineering at the Indian Institute of Technology, Madras. The first few semesters were an extension of the anodyne academics at school till I sat through a course on Dynamics of Machinery taught by Dr. V. Ramamurti. Boy, could he teach. I spent the remaining semesters at college doing every course he offered, and developing an appreciation of both engineering mechanics and engineering judgment.

The next few years were equally formative and shaping. I spent two of these working for a Master’s Degree under the stellar guidance of Dr. Eric Becker at the University of Texas at Austin. In between discussing motorcycles, the appalling state of some leading textbooks, the discipline of computer programming, the art of literature surveys and the difference between a college-degree and education, he taught me most of what I now know about the Finite Element Method. Degree in hand, it was off to the Tata Research, Development and Design Center at Pune where Dr. E. C. Subbarao was all you could ask for in a boss. The lessons I learnt from him on managing people have stayed with me since.

While my own job involved applied research using finite element and finite difference methods, it was educative to watch as TCS, TRDDC’s parent company, took up the distribution of Unigraphics in India. The lure of computer graphics was strong, and I moved to OMC Computers, a Hyderabad based company that distributed Silicon Graphics computers together with a wide range of scientific software.  The market for FEA was challenging, so the obvious thing to do was take that challenge head on by starting a company to focus on CAE and CAD. SDRC’s I-Deas on Windows NT was my platform of choice, and as the company grew we took up the distribution of I-Deas, provided design services to the automotive, power and defense sectors, and distributed HyperWorks. Growth often brings home the lesson that small can be beautiful too. After some introspection and evaluation of our priorities for life, Shaila and I sold the business to start KFour Metrics in November 2006.

In 2014 I chanced upon an interview with John Chawner of Pointwise which made us sit up and think. Experience with computational mechanics had shown that preprocessing is inelegant, and sometimes downright ugly. Could this product that had seen decades of work on a subset of preprocessing for CAE – grid generation specifically for CFD – be worth looking at? It helped that in the interview John criticized one of my pet hates – the “democratization” of CAE. We called Richard Matus to find out what Pointwise was doing in India, and here we are: distributing Pointwise in India.

  • Location: Hyderabad, India
  • Current position: Partner, KFour Metrics
  • Current computer: HP Laptop with Windows 8.1 and Dell Workstation with Linux Mint.
  • One word that best describes how you work: Patient

What software or tools do you use every day?

Firefox, Windows Live Mail, Libre Office, K-9 and Signal. And, of course, Pointwise.

What does your workspace look like?

Venkatesh's current workspace.

Venkatesh’s current workspace.

My dislike of air conditioning means I prefer wide open windows and a slowly swirling ceiling fan. This doesn’t always sit well with Hyderabad weather, where summers sometimes cross 45 degrees Celsius, but I continue to hold out. I rely on SpeedFan to let me know when the machines need a break.

My main workspace is a large, flat table on which I pile things as they come in. I often have multiple tasks going on at the same time, which makes for multiple piles, each of which I tend to leave undisturbed till the task is complete. Since some projects take quite a while before I finish, it can get messy at times.

The walls are lined with cupboards double-stacked with books. Many of these are indispensable technical references but some are there just for the joy of possession. The pick of the latter is a 1910 edition of “Theoretical Mechanics” by Percey F.Smith and William Raymond Longley. I come from a line of reading-addicts, so the bookshelves also house a collection of fiction and non-fiction going back to the early 1930s.

What do you see are the biggest challenges facing CFD in the next 5 years?

Of the technology challenges, dealing with CAD data is easily at the top of the list. A better concealed, and therefore more pernicious, problem is the tendency of improvements in user-interfaces to lull engineers into complacency. The first page of printed output from any FE application consists of a here-be-dragons warning. How many users even see printed output today?

What are you currently working on?

We’re looking forward to hosting Pointwise in India later this year, and are spending our energy working on making sure Pointwise users here can get the most out of this.

What would you say is your meshing specialty?

I can’t pick out any single area as a specialty. I’ve logged enough time in this field to find all types of meshes equally engrossing, but coming from long experience with FE meshing, T-Rex is fascinating. Local stoppage and prism recombination are both remarkably obvious and remarkably impressive once you see them in action.

Any tips for our users?

That’s easy: Glyph. Invest the upfront time in learning Tcl and you will find the API is a pretty logical extension of interactive Pointwise usage.

What project are you most proud of and why?

Once case that really stands out is when Pointwise delivered a grid that had about half the cells the analyst had braced for, even while maintaining resolution in areas of interest and with a significantly better grid quality. Can’t say more than that without crossing the confidentiality-limit!

What CFD solver and postprocessor do you use most often?

I don’t do much with CFD solvers beyond checking grids. OpenFOAM, SU2 and Fluent are the ones I use from time to time. For post-processing, ParaView rules.

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

My immediate interest centers around overset methods. A Direct Cut Approach for Overset Hole Cutting” (Ralph W. Noack, 18th AIAA Computational Fluid Dynamics Conference, June 25-28 2007, Miami, FL) and “Best Practices in Overset Grid Generation” (William Chan, Reynaldo Gomez, Stuart Rogers, Pieter Buning, AIAA 2002-3191) head the list of papers I’m currently studying.

Do you plan on attending any upcoming conferences or workshops?

I will be at the 2016 Pointwise User Group Meeting in late September. Schedule permitting, the ICFMFA 2017 and the Aeronautical Society of India’s Annual CFD Symposium are on my wish-list for 2017.

What do you do outside the world of CFD?

I find it very hard to understand art. It doesn’t seem to yield to hard work. The nut I’ve been trying to crack for the past 11 years and counting, is music. I play in a small band that meets as often as it can, given our different schedules. Sometimes it feels like the band sessions are more about arguing how to play what and why, but we do make progress.

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

To exercise extreme skepticism about the output of any computer simulation.

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

If you’re a vegetarian, as I am, the thali at The Spicy Venue in Jubilee Hills is hard to beat.

Posted in People & Places | Tagged , , , , , , , , , , , , , , , , | Leave a comment

This Week in CFD

Software

pointwise-v18-uns-quad-hex-source-4000x2400

A mesh from Pointwise Version 18 illustrating quad-dominant surface meshes, hexahedral layer extrusion, and a source for tetrahedral mesh clustering control.

  • Congratulations to Stuart Rogers and his team at NASA Ames for the selection of Pegasus 5 as 2016 NASA Software of the Year. Pegasus 5 is used to assemble overset grids prior to simulation in an overset CFD solver. See image below. [Pointwise’s overset grid assembly capability includes a direct interface to Pegasus 5.]
  • Pointwise Version 18, released earlier this week, includes quad-dominant surface meshing, unstructured hexahedral layer extrusion, and tetrahedral clustering sources.
  • Meshing is only one aspect of recently released Simpleware 2016.09. Be certain to watch the video.
  • The SolidSmack blog delved into SIMIT, the new, open-source, simulation language mentioned here previously. Again, be certain to watch the video.

Applications

pegasus5-nasa-soy-2016

This overset grid for the space shuttle’s external tank is typical of the complexity of cases that Pegasus 5 can assemble. It is impossible not to love a grid image like this. See article link above. Image from NASA.

  • The Ahmed Body is back in a paper by Envenio that compares performance of their EXN/Aero solver with the performance of ANSYS Fluent and STAR-CCM+.
  • On Engineers Rule, you can read about CAD data exchange and some of the issues involved. If you’ve never thought about the details of this before, it’s worth a read. [One nitpick: “I have always considered IGES to be more of a wireframe protocol.” I may be IGES’ last defender on the planet but IGES is a robust standard for surfaces and solids (i.e. B-Rep Solid Model Object, entity 186) if written correctly – which experience has shown me most software does not do.]
  • Resolved Analytics wrote a comparison of popular CFD software packages.
  • Do you work with valve stems? Here’s an article describing how to simply generate brick meshes for them.
  • OneSails Australia uses CFD in the design of sails for yachts.

News & Reading

workstations-for-sim-ansys

Visualization of an ANSYS Mechanical 17 simulation from the article below about workstation performance. Image from DEVELOP3D. See link below.

  • Desktop Engineering magazine is now Digital Engineering.
  • FYFD blogger and fluid dynamics maven Nicole Sharp will give a 24/7 lecture at this year’s Ig Nobel Prize Ceremony. [A 24/7 lecture involves presenting your material twice – first in 24 seconds, then using only 7 words. How could we do this for meshing?]
  • You have a little less than two months to submit your entry for the ANSYS Hall of Fame.
  • The Femap blog shares information from a recent study that reveals how top performing companies use simulation.

Computing

  • Despite being about FEA and not CFD, DEVELOP3D’s article on workstation performance for simulation is a worthy read. Using ANSYS Mechanical 17 as a benchmark, their conclusions (if I understand them correctly) are: solid state disk is a no-brainer, RAM is worthwhile, but don’t get seduced by CPUs.
  • Cray and LS-DYNA offer a white paper (registration required) on a fan-off simulation of a jet engine.
  • The Piz Daint supercomputer is being used for CFD, specifically one of the entries for the Gordon Bell Prize. [In case you had the same question as I, Piz Daint is a mountain peak in the Swiss Alps.]

Mickey-Mesh Mash-Up

You know by now that I am easily amused (in other words, I suffer from chronic shiny object syndrome). In particular, I enjoy when two or more of my interests get mashed-up. The image below is a vintage animation of Mickey Mouse and a grid. I’m fairly certain (because I don’t remember where I found the image) it’s from the Disney film Thru the Mirror from 1936. If you go to that link and read more, you’ll find another image of Mickey and a grid near the end.

mickey-mouse-mirror-grid

Even Mickey Mouse is into grids.

Note: Please remain calm, but due to travel, the Pointwise User Group Meeting 2016, and the International Meshing Roundtable, there may not be another This Week in CFD until October. I will see you at two of those events, right?

Posted in Applications, Events, Hardware, News, People & Places, Software, Uncategorized | Tagged , , , , , , , , , , | Leave a comment

This Is How I Glyph – Uniform Unstructured Domain Refinement

uniformdomrefinement

Previously I wrote about a Glyph script that performs automatic grid refinement. That script starts with refining connectors, then domains, and finally blocks. For unstructured grids, domains are initialized using their bounding edges. The simple action of refining a connector, also refines any adjacent domains. Due to the nature of the Delaunay and Advancing Front domain triangulation techniques, a change in boundary points prompts reinitialization of the domain. That means triangles are not subdivided, but rather recomputed based on updated boundary information. So, if you’re looking for a script that performs uniform unstructured domain refinement by subdividing triangles, then this next script is for you!

UniformDomRefinement.glf takes a collection of unstructured domains and refines them by using either edge midpoints or element centroids to create additional cells on the surface. The number of refinement steps can be specified allowing you to create an entire grid family. Once the mesh has been refined, the original mesh can be retained or removed if desired. Lastly, you have the option of placing the family of refined domains in the current working layer, or in successive empty layers to improve the organization of your grid family.

And there you have it—two Glyph scripts that you can use to help perform automatic grid refinement. To download the UniformDomRefinement.glf script directly, you can use this link. If you would like to visit the repository on GitHub, then please visit https://github.com/pointwise/UniformDomRefinement.

Do you have an idea or a Glyph script you’ve written that you would like to share with us? Let us know in the comments below or on Twitter @Pointwise.

Happy scripting!

Posted in Applications | Tagged , , , , , , , , , | Leave a comment

Pointwise V18 Now Available

A major new release of Pointwise for CFD mesh generation is now available for download and production use. It includes the biggest change to our core meshing technology since the addition of T-Rex for boundary layer resolving hybrid meshes in 2007. Specifically, you now can:

  • generate quad-dominant surface meshes
  • extrude unstructured hexahedral layers for boundary layer resolution
  • use sources to control tetrahedral mesh clustering away from the geometry
  • and a lot more

You can see more of what’s in Pointwise Version 18 on our What’s New page.

pointwise-v18-uns-quad-hex-source-600x360

Posted in News, Software | Tagged | Leave a comment

This Week in CFD

Mistakes and Failure

  • ENGINEERING.com shares six of the most embarrassing simulation mistakes you can make [and I’m willing to be we’ve all done one of them at least once. For example, #3 mixing SI and Imperial units.]
  • And in the same vein we read ten steps to successfully fail at CFD. #3 Never do CFD with small meshes. [This is a nice segue to…]
  • Read about mesh settings for FEA in Autodesk Simulation. [Who can resist a blog post series called “Sim with Jim”?]
  • Altair Hyperworks has been updated for aerospace applications by improving model-building workflows.
Screen capture of a video showing an ANSYS Fluent simulation of a gravity-driven toilet flushing. My favorite tweet from today's #SimulationFriday. Click image for video.

Screen capture of a video showing an ANSYS Fluent simulation of a gravity-driven toilet flushing. My favorite tweet from today’s #SimulationFriday. Click image for video.

Events

Reading

Computing

  • Simit is a new programming language that can speed-up simulations by a factor of 200 by coupling the graphical and matrix definitions of a system.
  • And when it comes to exascale computing, do we collectively know how to measure it and relative to what? This video lecture on exascale’s goals and baseline is worth watching. [“The beginning of wisdom is the definition of terms.” -Socrates]

In Other News…

  • ANSYS is getting a new CEO: Dr. Ajei Gopal will replace Jim Cashman on 01/01/2017, as reported by Monica Schnitger.
  • CPFD Software (makers of Barracuda) has formed a technical advisory board.
  • Aviation Week and AIAA are seeking nominations for their 2017 20 Twenties awards to recognize “top university talent” (i.e. twenty twenty-something students who are on track to be future leaders in aerospace.
  • And while we’re talking aircraft, will plasma wings truly change air travel?
  • And while we’re talking boats, will a stern hydrofoil truly change shipping?

Grids Light Up The World

Just so you don’t think I’m all talk (or text as the case might be) when it comes to this “mesh art” stuff, here’s a photo of a new toy I bought that is another example of meshes IRL. This is a 3D Illusion LED Lamp called “Space.” It’s only one of many meshed designs available from an online store I just happened to run across – Touch of Modern. This lamp has several different mode settings that make it change colors.

"Space," one of the 3D Illusion Lamps available at Touch of Modern. See link above.

“Space,” one of the 3D Illusion Lamps available at Touch of Modern. See link above.

Note: I have no affiliation with Touch of Modern whatsoever and received no compensation of any kind for mentioning their products and website.

BONUS: You have until 30 September 2016 to enter Science Magazine’s Dance Your PhD contest. I don’t know what’s more disturbing – the dancing or the fact that this year’s contest is the 9th annual.

Posted in Applications, Events, Hardware, News, People & Places, Software | Tagged , , , , , , , , | Leave a comment