Evaluation of reduced-order aeroelastic simulations for shock-dominated flows

Aeroelastic predictions of a thin panel in supersonic flow with a shock/boundary layer interaction (SBLI) are evaluated relative to wind tunnel experiments. Measured time histories of the panel displacement and velocity show stationary deflections as well as post-flutter oscillations for a range of shock impingement strengths. The fully coupled, computationally efficient aeroelastic modeling framework is formulated with a nonlinear structural reduced-order model and quasi-steady enriched piston theory aerodynamics. The aeroelastic model predicts the observed shape of the stationary responses with correlation coefficients larger than 0.8 for all SBLI conditions. In regards to dynamic responses, the model captures flutter onset as well as the post-flutter periodic oscillations for attached SBLI. The system's sensitivity to different initial conditions and shock impingement location is also investigated for attached SBLI. Shock-induced flow separation emerges as the SBLI strength increases. For the strongest shock, the computations predict flutter but do not capture the frequency content of the measured post-flutter response. This discrepancy is tied to the breakdown of the quasi-steady flow assumption in piston theory with increasing flow separation and highlights the need for unsteady flow models.