The boundary layer development downstream of a shock interaction at an expansion corner

Boundary layer developments were measured the flow downstream of an expansion corner when the boundary layer is disturbed by a shock wave striking the surface near the corner. It was found that most velocity profiles quickly relax to a near equilibrium state in about 8 to 16 boundary layer thicknesses with the distance depending on the shock strength. The boundary layer developments are in fair agreement with the predictions from an eddy-viscosity model when the incident shock is weak. For stronger shocks the calculated profiles from the eddy-viscosity model and from Bradshaw's turbulent energy method are similar, but both fail to predict the measured boundary layer development. However, the agreement was much improved if the calculation was started from the first measured profile after the shock interaction, and the prediction from the eddy-viscosity model was further improved if an exponential lag equation was used to account for the transport properties of the turbulence.