Study of fluid-structure interaction under a shock/boundary-layer interaction in Mach 2 flow using synchronous 50 kHz PIV and 5 kHz DIC*

Fluid-structure interaction (FSI) is a phenomenon where the structural motion responds and couples to the flow field.  For instance, in supersonic/hypersonic flight, the frictional heating of the flow can lead to increased compliance and the presence of shock-induced separation can lead to rapid fatigue of the structure. To understand the physics of FSI, an experimental investigation of a thin panel response under a compression-ramp-induced shock/boundary-layer interaction using simultaneous 50 kHz PIV and 5 kHz stereoscopic DIC has been conducted. Streamwise (U), wall-normal (V) velocities and out-of-plane displacement have been measured. The effect of the mean panel deformation has been noticed: the average U velocity near the wall has been shown to change its magnitude in response to the streamwise slope of the panel deformation. Furthermore, the cross-correlation between the V-velocity fluctuation and the mean-subtracted panel displacement has been evaluated. The strong correlation results suggest that the flow remains tangent to the wall surface as the panel undergoes low-frequency deformation. Lastly, the possible coupling mechanism between the panel displacement and the unsteady dynamics of the separation shock motion will be discussed.