Wall pressure coherence in supersonic turbulent boundary layers

A numerical database (Bernardini & Pirozzoli, Phys. Fluids, vol. 23, 2011, 085102) is analysed to investigate cross-statistics of wall-pressure fluctuations induced by supersonic turbulent boundary layers developing over a rigid smooth wall without a pressure gradient. The Mach number spans from 2 to 4 and a relatively large range of Reynolds numbers is considered. It is shown, for the first time, that the cross-statistics of wall-pressure fluctuations at such high Mach numbers is very similar to that usually observed in incompressible flow conditions. Furthermore, it is demonstrated that theoretical predictions provided by the well-known Corcos and Efimtsov models continue to apply.