Effect of Ramp-Induced Shock/Boundary Layer Interaction on the Vibration of a Compliant Panel at Mach 5

Abstract

The fluid-structure interaction of a compliant panel under a compression-ramp-induced shock/boundary layer interaction (SBLI) is investigated experimentally in a Mach 5 wind tunnel. A thin brass panel of dimensions L=121.9 mm (chord), W=63.5 mm (span) and h=0.254 mm (thickness) is installed flush with the floor of the tunnel test section. A 28◦compression ramp is installed downstream of the panel, creating a shock-induced turbulent separated flow with a separation length of approximately three boundary layer heights. Measurements of the panel vibration are performed using high-speed stereoscopic digital image correlation and the fluctuating surface pressure on the panel is measured using fast-response pressure sensitive paint. Clear evidence is found that the SBLI surface pressure fluctuations are significantly affected by the panel vibration. Importantly, the pressure standard deviation in the intermittent region increases by 50% due to surface compliance when compared to a rigid panel baseline case. Analysis also shows the shock foot motion is strongly correlated with the panel vibratory response. In addition, the panel vibration increased by several orders of magnitude in the presence of the SBLI as compared to the case with Mach 5 flow but without a ramp present. The importance of coupling between the SBLI and panel vibration is discussed and a possible mechanism of the coupling is suggested.