Studies on the Control of Shock Wave-Boundary layer Interaction Using Steady Microactuators

摘要

An array of high momentum steady microjets was placed upstream (x/δ_o = -12.2) of a 24° unswept compression ramp in a Mach 2 flow to study their effect on the unsteady pressure loads due to the interaction. Flow visualization and fluctuating pressure measurements were obtained in the separated shock wave/boundary layer interaction produced by the ramp. Results show that the array of microjets issuing in the supersonic crossflow creates a shock which effectively reduces the Mach number in front of the separation shock. This causes the separation shock to weaken, and move upstream by as much as 4δ_o from its mean undisturbed location. The mean pressure distribution was altered due to the microjet control with a maximum reduction of 7% on the wall surface downstream of the separation shock and 25% on the ramp surface. The wall pressure fluctuations were also reduced significantly in the separation region with control where the intermittent region was also reduced by more than 40% with the applied control. The pressure spectra show that the unsteadiness on the wall and the ramp surfaces has been significantly reduced with the applied control.