Studies on the Influence of Steady Microactuators on Shock-Wave/Boundary-Layer Interaction

An array of high-momentum microjets are used upstream of a compression corner to control the shock-wave/boundary-layer interaction on a 24 deg unswept compression ramp in a Mach 2 flow. Measurements include schlieren flow visualization and unsteady pressure measurements using fast-response pressure sensors of the interaction region. Results show that the array of microjets issuing in the supersonic crossflow create oblique shocks, which effectively reduce the incoming Mach number at the compression corner. This leads to a modified separation shock of significantly reduced strength. The location of the modified shock is moved upstream by as much as 4 delta(0) from its mean undisturbed location. The mean pressure distribution on the surface is altered with microjet control leading to a more gradual compression of the incoming flow relative to the separation shock without control. The wall-pressure fluctuations in the interaction region are reduced by approximately 50%, and the flow near the compression corner appears to be energized with control, based on the unsteady surface-pressure measurements. The pressure spectra show that microjet control results in a redistribution of energy on the wall and the ramp surfaces.