Response of a cantilevered plate to shock impingement in hypersonic flows

Abstract

The presence of shock wave boundary-layer interactions (SBLI) on thin and compliant panels adds complexities to vehicle design. Shock waves impose an adverse pressure gradient across it, leading to high loads and resulting in a separated flow. The interaction of the flow field with lightweight vehicle structures or thin panels results in highly nonlinear aeroelastic behavior, which can lead to undesired consequences. This work focuses on fluid-structure interactions on a thin panel induced by shock impingement at Mach 6.5 flow. A wedge of 24.7 degrees generates a shock wave and impinges on the thin panel, which is in a cantilevered configuration. This gives rise to flow-induced vibrations and creates aeroelastic coupling between the panel and the flow field. The coupling between the flow field and panel is analyzed using high-speed Schlieren photography for flow visualization and accelerometers to characterize structures’ responses. The structural panel modes deduced from accelerometer data have been compared with measurements from impact hammer tests. The spectral content of the accelerometer data reveals the change in structure response when SBLI is present, which shifts the first mode’s peak frequencies to higher frequencies. A set of experiments without shock impingement were conducted to compare the structural response in the presence of SBLI. These were then compared with runs with shock impingement on panels. The effect of different panel thicknesses and mass ratios on the structure response was investigated. Dynamic mode decomposition was performed for the compliant panels to understand how the compliant panel affects the flow field. Dominant flow frequencies and panel vibration modes excited by the panel were identified.