Investigation of aeroelastic instabilities for a thin panel in turbulent flow

The dynamic response of a thin buckled panel in a supersonic wind-tunnel experiment is investigated. Measured time histories of the panel displacement and velocity show co-existing, nonlinear responses with features of periodic and chaotic oscillations. Fully coupled computational analyses are conducted in order to study and interpret the aeroelastic phenomena observed during the experiments. A computationally efficient modeling framework is formulated with a nonlinear structural reduced-order model and enriched piston theory aerodynamics for the mean flow. The simulations predict the onset of the chaotic motions observed in the experiments, albeit with an approximately 21% increase in the oscillation amplitude. A linearized equation governing the distance between neighboring solutions is derived and used to compute the largest Lyapunov exponent in order to prove the existence of chaos. A modified Riks analysis highlights the co-existence of multiple equilibrium positions which predisposes the nonlinear system to chaos. The system’s sensitivity to cavity pressure, temperature differential, and initial conditions is also investigated. Variation of the cavity pressure and temperature differential yields additional regions of dynamic activity that were not explored during the experiments.