AIAA SciTech Recap

With everyone home and all caught up with work, now is probably a good time to sit back, relax, and reflect on AIAA SciTech (Science and Technology Forum and Exposition) which was held a couple weeks ago in National Harbor, Maryland.

The Pointwise booth on the AIAA SciTech exhibition floor.

This year we participated in a variety of events. Five of us left a balmy 60 degrees in Texas for the Washington D.C. area to work the booth, chair sessions, and present our work. It would be a busy week, but one we look forward to every year.

On Monday morning I attended the the Meshing Technology and Application session. Scanning the room revealed several familiar faces in the meshing community, including the Pointwise crew. I arrived in time for a talk regarding Automated Tetrahedral Mesh Generation for CFD Analysis of Aircraft in Conceptual Design. The presenter defined a design methodology wherein one could go from a geometry in OpenVSP, a parametric aircraft modeler, to a CFD ready tetrahedral volume mesh. I was so intrigued by the concept that I later took a surface mesh from OpenVSP, automatically generated a tetrahedral volume mesh using Pointwise, and ran a CFD calculation using OpenFOAM. An interesting talk followed by a burst of productivity is a great way to start the week!

Pointwise was used to automatically generate an unstructured volume mesh for an OpenVSP model. The CFD solution for the Cirrus SR22 aircraft was computed using OpenFOAM.

Pointwise was used to automatically generate an unstructured volume mesh for an OpenVSP model. The CFD solution for the Cirrus SR22 aircraft was computed using OpenFOAM.

John Dreese describing the 6DOF simulations he performed while working at Lockheed Martin on store separation.

John Dreese describing the 6DOF simulations he performed while working at Lockheed Martin on store separation.

Later that afternoon John Dreese, a Senior Engineer on our Technical Support team, joined Lockheed Martin’s Dennis Finley and Ed Blosch to discuss their store separation work. Their paper titled Comparison of CFD-Based Simulation of External Fuel Tank Separation to Flight Test described the role CFD played in the analysis of fuel tank separation and how well it compared with the flight test data. John described his trajectory analysis work using the ADAMS Toolkit for 6DOF simulations. As I learned, store separation can be tricky, and the goal of projects like this are to accurately predict the physics and prevent erratic separation behavior.

Wrapping up Monday, I had the pleasure of presenting to the Conceptual Aircraft Design Working Group (CADWG), a subcommittee of the Aircraft Design Technical Committee. The President of Design, Analysis and Research Corporation, Dr. Willem Anemaat, had invited us to talk about our software and how it can be used during the preliminary design phase. The title of the talk was Integrating CFD Mesh Generation Into the Design Cycle and through a number of applications I described how Pointwise can be used to accelerate the design of real-world systems. A member of the CADWG subcommittee even tweeted about something he learned from the world of mesh generation. The presentation went well and was followed by a lively Q&A session.

One question I was asked was, “What major hurdle must we overcome in order to have fully automatic meshing?” CAD interoperabilty and adaptive meshing aside, in my opinion it is difficult to replace engineering intuition. It is the responsibility of an engineer to understand the physics of the problem and identify locations where the grid must be refined in order to resolve the gradients necessary to improve solution accuracy. Taking the engineer out of this process and automating mesh generation from start to finish would be a tall order in any industry. However, that being said, we have customers using Pointwise to automatically generate grids for specific problem types often isolated to a single industry. But generalizing this automatic meshing workflow across all industries still remains the holy grail of mesh generation.

A detailed look at the multi-block structured topology surrounding the NASA 30P30N 3 element high-lift airfoil. This grid was assembled for a computational aero-acoustics simulation.

A detailed look at the multi-block structured topology surrounding the NASA 30P30N 3 element high-lift airfoil, an example from my CADWG presentation. This grid was assembled for a computational aero-acoustics simulation.

Phoenix Integration also presented to the CADWG committee and introduced their software for integrating a variety of analysis codes under a unified framework. The resulting workflow can be automated to optimize the design of a constrained system. A brake pad example was presented, demonstrating the ease with which the process could be automated and leveraged to explore the possibility of higher performing alternative designs.

On Wednesday morning Carolyn Woeber, Pointwise Technical Support Manager, co-chaired one of the 2nd High Lift Prediction Workshop sessions. The goal of the workshop was to determine the current state of the numerical prediction capabilities for high-lift aircraft configurations, namely the European High Lift Programme (EUROLIFT) DLR F11 geometry for this year’s workshop, in take-off/landing phases of flight. This allows engineers to develop a better understanding of the flow physics involved so that more accurate prediction methods can be developed. A number of studies were performed over a range of angles of attack and Reynolds numbers using a variety of flow solvers and grid systems. We learned that our hybrid grids generated using Pointwise’s T-Rex meshing algorithm were the only unstructured grids that were able to capture the wake over the flap from the upstream elements.

Unstructured surface mesh for the DLR F11 aircraft in high-lift configuration with the slat track and flap track fairings included.

Unstructured surface mesh for the DLR F11 aircraft in high-lift configuration with the slat track and flap track fairings included.

Walking into the Overset Grid Methods session on Wednesday I was pleasantly surprised to see so many people. I arrived in time to see the Pointwise Vice President of Research and Development, Dr. John Steinbrenner, explain the work he did with Nick Wyman, the Director of Applied Research. I took one of the remaining seats in the back of the room and listened to John talk about Automatic Structured and Unstructured Grid Cell Remediation for Overset Meshes. For those of you generating overset meshes, the technology presented in this talk will save you time by allowing the grid to adapt and resolve cell size disparities between block interfaces.

Result of cell remediation in the tight gap between the unstructured surface meshes that define the pylon and store geometry.

Result of cell remediation in the tight gap between the unstructured surface meshes that define the pylon and store geometry.

Overall it was a great week. The booth was busy and the sessions were captivating. But none of this would have been possible without the attendance of people from around the world. We enjoyed the opportunity to talk with old friends and meet new people, all while learning a little bit more about the industries we support. We all hope you enjoyed the conference as much as we did.

If you didn’t have a chance to stop by and see us this time, we’ll be attending AIAA Aviation in Atlanta, Georgia in June. For a full list of events we’ll be attending this year, please visit http://www.pointwise.com/events/.

About Travis Carrigan

A Pointwise engineer helping other engineers solve their meshing problems.
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2 Responses to AIAA SciTech Recap

  1. Seung Yoo says:

    I see that most of the discussion and papers are focused on the unstructured mesh generation techniques. Were there any discussion/focus on the structured meshing and topology generation technique?

    • Travis Carrigan says:

      I did talk a lot about unstructured meshing in my post. But yes, there were papers that discussed structured meshing. Unfortunately, the only papers I attended are the ones highlighted in this article.

      I know that in the High-Lift session some of the grids they used were multi-block structured and structured overset. Also, a large portion of John Steinbrenner’s work focused on structured overset remediation.

      Digging through the conference proceedings many of the wind turbine papers, and turbomachinery in general, utilized structured topologies. Aero-acoustics is another area where I noticed structured grids being used heavily.

      I hope I was able to answer your question.

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