Proper Orthogonal Decomposition of Streamwise-Velocity Fluctuations in a Compression-Corner Shock-Wave/Turbulent Boundary-Layer Interaction

Abstract

In this work, we use snapshot proper orthogonal decomposition (POD) to analyze shock-wave/turbulent boundary-layer interactions (SWBLI) in the compressioncorner configuration. Using Krypton Tagging Velocimetry (KTV), we study the flow of a 99% N2/1% Kr gas mixture over 8 ◦, 16◦, 24◦ and 32◦ compression corners at M = 2.8 and ReΘ = 1750. The experiments were performed in the AEDC Mach 3 Calibration Tunnel (M3CT) and the resulting KTV derived velocity fields are decomposed using POD to investigate the turbulent structure of the flows. From the POD results, we extract the dominant flow structures and compare each case by presenting mean-velocity maps that correspond to the largest positive and negative POD mode coefficients. This analysis allows us to relate POD modes with flow features such as separation, and also asses the effect of the wedge angle on the structure of the modes. Finally, the POD spectrum reveals an inertial range common to the incoming boundary-layer and each compression-corner flow that is present after the first ≈ 10 dominant POD modes.