Convection velocity in supersonic turbulent boundary layers

The convection velocity of large-scale organized motions was measured in a Mach 3 boundary layer using streamwise-separated hot wires. The broadband convection velocity, determined from space-time correlations, is 0.9U∞ across the entire outer region of the boundary layer. The convection velocity of individual structures was deduced using a pattern recognition technique, and this revealed that the majority of the large-scale structures convect at nearly the same velocity. A comparison of the present results to previous measurements indicates negligible Reynolds number and Mach number effects on convection velocity.