Supersonic shock/turbulent boundary-layer interaction on a roughened surface

This article presents results from an exploratory study of roughness effects on shock-generated turbulent shock/boundary-layer interaction that specifically focuses on a small sand grain type of roughness that tells within the framework of the law of the wall. With regard to the interaction zone itself, a triple-deck model is used to develop a theory of how such roughness alters the interactive flow physics. Some confirming experimental results are then given from a Mach 2.5 supersonic wind-tunnel study of both nonseparating and incipiently separating wedge shock-generated turbulent interactions on several roughened surfaces. These results show that even a small roughness significantly increases the upstream influence and enhances the onset of separation.