Experimental Study of a Mach 3 Compression RampInteraction at Re{theta} = 2400

Abstract

Experiments were performed to investigate the flow in a Mach 2.9 shock wave turbulent boundary-layer interaction at a Reynolds number based on momentum thickness of 2400. The flow configuration was a nominally two-dimensional 24 deg compression ramp, which exhibited a separation bubble in the corner region. Mean flow quantities, including the velocity profile upstream and downstream of the corner, and the wall pressure through the interaction were measured. Filtered Rayleigh scattering was used to visualize the flow structure in the interaction and provide quantitative measurements of the turbulent structure angle and the intermittency of the boundary-layer edge turbulence. The shock motion was characterized by measuring the fluctuating wall pressure. The results indicate that, compared to previous measurements obtained at higher Reynolds numbers of 60-80,000, the separation bubble is approximately twice as long, the root mean square of the wall-pressure fluctuations has a relatively smaller peak, and the intermittency of the wall-pressure signal in the shock-foot region is attenuated. As in the high-Reynolds-number case, the shock motion has a broadband frequency distribution with a peak slightly below 1 kHz. The mean flow quantities, root mean square wall-pressure-fluctuation profile, wall-pressure signal, and shock-motion frequency agree well with the direct numerical simulation of a previous study at matching conditions.