PIV Measurements of Shock/Cooling-Film Interaction at Varying Shock Impingement Position

Abstract

A supersonic film-cooling configuration with shock interaction is investigated experimentally by means of high-speed particle-image velocimetry. A laminar cooling film is injected at an injection Mach number of $Ma_i=1.8$ beneath a turbulent boundary layer at a freestream Mach number of $Ma_\infty =2.45$. A flow deflection of $\beta =5^\circ$ generates a shock wave which impinges upon the cooling film. The influence of the impingement position of the incident shock on the cooling film is analyzed by the time-averaged velocity fields and Reynolds shear stress distributions. The results show a significantly, shock-induced increase of the turbulent transport. Shock impingement close to the injection nozzle equally increases the Reynolds shear stress in the shear layer and in the boundary layer on the bottom wall. An impingement position further downstream drastically increases the turbulent transport in the boundary layer, however, in the shear layer the increase in turbulent transport is lower.