Features of shock-induced panel flutter in three-dimensional inviscid flow

Abstract

Oblique shockwaves may impinge on supersonic vehicles internally in an engine or externally on the outer mold line. They create a severe loading environment and may induce dynamic instabilities such as panel flutter. This study computationally explores the effect of shock-induced panel flutter response in 3D, inviscid, Mach 2 flow. Flutter behavior of a square panel is compared across several incident shock angles and inflow dynamic pressures. The presence of an impinging shockwave is found to produce panel flutter that is characteristically different than the shock-free condition. The response contains significantly larger local pressure gradients, larger spanwise variations, and higher-order modal activity in the panel. Results are also compared to two-dimensional inviscid flow over an infinite-span panel. The 3D centerline is found to compare closely with 2D simulations. However, away from the centerline, 3D effects have a significant influence on the solution. In general, stronger oblique shockwaves raise flutter amplitude and frequency, while weaker shockwaves stabilize the panel response. These latter findings indicate important considerations for both structural lifing and flow control applications.