Evaluation of Linear, Inviscid, Viscous, and Reduced-Order Modeling Aeroelastic Solutions of the AGARD 445.6 Wing Using Root Locus Analysis
Speaker: Walter A. Silva, Aeroelasticity Branch, NASA Langley Research Center
Presentation
Seminar Slide Deck (PDF-2.3MB)
Abstract
Reduced-order modeling (ROM) methods are applied to the CFD-based aeroelastic analysis of the AGARD 445.6 wing in order to gain insight regarding well-known discrepancies between the aeroelastic analyses and the experimental results. The results presented include aeroelastic solutions using the inviscid CAP-TSD code and the FUN3D code (Euler and Navier-Stokes). Full CFD aeroelastic solutions and ROM aeroelastic solutions, computed at several Mach numbers, are presented in the form of root locus plots in order to better reveal the aeroelastic root migrations with increasing dynamic pressure. Important conclusions are drawn from these results including the ability of the linear CAP-TSD code to accurately predict the entire experimental utter boundary (repeat of analyses performed in the 1980's), that the Euler solutions at supersonic conditions indicate that the third mode is always unstable, and that the FUN3D Navier-Stokes solutions stabilize the unstable third mode seen in the Euler solutions.
Biography
Walter A. Silva is a senior research scientist in the Aeroelasticity Branch at the NASA Langley Research Center. He received his B.S. (Aerospace Engineering) from Boston University, M.S. (Aerospace Engineering) from Polytechnic University (NY), and PhD (Applied Mathematics) from the College of William & Mary. His interests include computational and experimental aeroelasticity/aeroservoelasticity, reduced-order models, system identification, computational fluid dynamics, and nonlinear dynamics. Dr. Silva is the NASA-wide Technical Lead for Aeroelasticity/Aeroservoelasticity for NASA’s Commercial Supersonic Technology (CST) Project. Dr. Silva has thirty years of experience working in industry, government, and academia. While at Grumman Aerospace Corporation, he was awarded a Grumman Master’s Fellowship, working Loads and Dynamics including flutter analyses of the Shuttle Trainer Aircraft and the Tiltrotor vehicle. Dr. Silva is an Adjunct Professor in Applied Mathematics (College of William & Mary) and in Aerospace Engineering (Old Dominion University). Dr. Silva has taught several invited short courses across the country and around the world including Boeing, Gulfstream, Instituto Tecnologico de Aeronautica (ITA, Brazil), Universidade de Sao Carlos (Brazil), Embraer, Delft University, and many other organizations. He pioneered application of the Volterra theory to nonlinear unsteady aerodynamics and aeroelasticity and is the recipient of NASA’s Exceptional Achievement Medal for his contributions in the development of unsteady aerodynamic reduced-order models. Dr. Silva has obtained a patent on his reduced-order modeling methodology. Dr. Silva is a NASA Floyd Thompson Fellow, an Associate Fellow of the AIAA, and an Associate Editor for the AIAA Journal.