I’m Zach Davis and This Is How I Mesh

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

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.

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.

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

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

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!

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.

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 21st through June 26th 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, 21st 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.

About Travis Carrigan

A Pointwise engineer helping other engineers solve their meshing problems.
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2 Responses to I’m Zach Davis and This Is How I Mesh

  1. Pingback: I’m Travis Carrigan and This Is How I Mesh | Another Fine Mesh

  2. Justus Benad says:

    Very nice and interesting article! Thanks!

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