NASA Interaction of Two Glancing, Crossing Shock Waves with a Turbulent Boundary-Layer at Various Mach Numbers

A preliminary experimental investigation was conducted to study two cross-ing, glancing shock waves of equal strengths, interacting with the boundary-layer developed on a supersonic wind tunnel wall. This study was performed at several Mach numbers between 2.5 and 4.0. The shock waves were created by fins (shock generators), spanning the tunnel test section, that were set at angles varying from 4 to 12 degrees. The data acquired in this investigation are wall static pressure measurements, and qualitative information in the form of oil flow and schlieren visualizations. The principle aim of this study is two-fold. First, a fundamental understanding of the physics underlying this flow phenomena is desired. Also, a comprehensive data set is needed for computational fluid dynamic code validation. Results of this study indicate that for small shock generator angles, the boundary-layer remains attached throughout the flow field. However, with increasing shock strengths (increasing generator angles), boundary-layer separation does occur and becomes progressively more severe as the generator angles are increased further