Characteristics of multiple shock wave/turbulent boundary-layer interactions in rectangular ducts

Abstract

Multiple shock wave/turbulent boundary-layer interactions in a rectangular duct have been investigated using wall pressure measurements, surface oil flow visualization, spark schlieren photography, and laser Doppler velocimetry. Two undisturbed incoming Mach numbers were considered, Mach 2.45 and Mach 1.6. At Mach 2.45 the shock structure was a neutrally stable pattern of oblique shocks followed by repeated normal shocks with the level of flow confinement having only a small effect in the interaction. A large, three-dimensional separation region was observed. At Mach 1.6 the pattern consisted of a bifurcated normal shock followed by weaker, unbifurcated normal shocks. The boundary layer under the bifurcated shock was incipiently separated. In contrast to the Mach 2.45 case, the lower Mach number interaction was much steadier with the length of the interaction scaling directly with the level of flow confinement.