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Launch Vehicle Aerodynamics Database Development for SLS

AMS Seminar Series

Speaker: Derek Dalle, Computational Aerosciences Branch, NASA Advanced Supercomputing Division

Presentation

Seminar Slide Deck (PDF-20.6MB)

Abstract

Launch vehicle aerodynamics is an interesting and sometimes ignored branch of aerosciences. It is a field that requires analysis of flow speeds from zero to Mach 20 and altitudes from sea level to low Earth orbit. This talk provides an overview of how these pieces fit together for the Space Launch System (SLS) program, with a particular focus on the contributions of the NASA Ames SLS CFD Team. Our main contributions are ascent aerodynamics (between Mach 0.5 and 5.0) and booster separation. These are both applications that require the generation of large databases. They are built out of CFD solutions that are not necessarily cutting-edge on an individual basis, but the thousands of solutions used to create each database are impressive when taken as a whole.

A common experience in launch vehicle aerodynamics is to have a small detail of the flow suddenly become very important to the program, while more obvious aerodynamic results like overall lift force attract little attention. Another aspect of this specialized field is that uncertainty estimates are often equally important to, or more important than, the nominal values. The talk will highlight some of the more interesting efforts from our group in understanding uncertainty quantification, including comparisons to experimental data, ensuring consistency of dispersed data, and a technique to provide uncertainty for non-scalar databases such as aerodynamic line loads. The talk will briefly discuss database management tools that were created by the Ames SLS CFD Team that are used for problem setup, running the flow solver, extracting data, creating databases, and documenting the results. Our group has used Cart3D, OVERFLOW, and FUN3D using a common interface to our database tool. Generating hooks for additional flow solvers at this point can be done quickly and easily. Finally, we will provide some general guidelines that we have developed over the years that may be useful to other CFD experts who are asked to generate aerodynamic databases for large programs.

Biography

Photo of Derek Dalle
Derek Dalle is a new hire in the NASA Ames Computational Aerosciences Branch (TNA). Previously, Derek was a contractor for Science & Technology Corporation in the same branch, since May 2014. He has spent most of his time at NASA working on aerodynamics for the Space Launch System, with a special focus on efficiency, organization, and database development. Before that Derek worked at Raytheon Missile Systems in Tucson, Arizona on high-speed vehicles. He received a Ph.D. in Aerospace Engineering from the University of Michigan in 2013, and his undergraduate degrees are from the University of Minnesota (2008).