An experimental investigation of the supersonic turbulent boundary layer subjected to convex curvature

Abstract

By employing particle image velocimetry, the impact of convex curvature on the supersonic turbulent boundary layer with inflow Mach number of 2.95 is experimentally investigated. The test models are carefully designed to have a zero-pressure-gradient convex boundary layer to isolate the influence of the streamwise pressure gradient while looking at the impact of convex curvature only. The results are compared with the favorable-pressure-gradient case (with pressure gradient parameter $\beta =-0.70$ ). For both of the zero-pressure-gradient and favorable-pressure-gradient convex boundary layers, the log law is found to be well preserved in the profile of streamwise velocity with inner scaling. Both of the mean streamwise velocity and the principal strain rate of the zero-pressure-gradient case collapse after scaling. By accumulating the streamwise velocity along the wall normal direction, the convex curvature is found to have the potential of diminishing the organized motion of the large scale vortices, which contributes to the stabilization of the turbulence.