Investigation on turbulent expansion-corner flow with shock impingement

Experiments are performed to study the interaction of an impinging shock wave and an expansion fan in a Mach 1.280 flow. The expansion fan neutralizes the pressure rise induced by the impinging shock wave. The mean surface static pressure shows a linear combination of the effect of both perturbations. Surface pressure fluctuations, which are associated with the characteristics of the perturbed boundary layer, indicate a transitional behavior. This is related to a nonlinear phenomenon arising the simultaneous action of the impinging shock wave and the expansion fan. The level of downstream pressure fluctuation depends on the overall inviscid interaction strength.