Prediction and Control of Unsteady Aeroelasticity for Future Aerospace Vehicles

We propose to develop a computationally efficient, potentially revolutionary method of modeling unsteady aeroelastic systems and controlling dynamic loads. Improving aerodynamic performance to meet the mission goals of next-generation civil/military aircraft and launch vehicles requires dramatically new methods of predicting and controlling nonlinear fluid-structure dynamics. The proposed innovation will provide a rational design tool for analysis and control of resonant fluid-structure interaction without compromising the effects of shocks, viscosity, separation, and shock-boundary layer interaction. Stability of a coupled fluid-structure system is accurately predicted in an eigenvalue formulation where eigenvalues correspond to coupled-system modal frequencies in the time domain and their growth rates. Limit cycle oscillations may then be computed and bifurcation diagrams constructed. The eigensystem formulation is tailored to accommodate state-of-the-art, frequency-based flow and structural controllers. The NASA Langley Aeroelasticity Branch and researchers such as Dr. Walter A. Silva maintain experimental aeroelasticity data from two programs-- Benchmark Active Controls Technology (BACT) and Actively Controlled Response of Buffet Alleviated Tails (ACROBAT)-- and these data will be used to validate the new computational method.