Multi-Measurement Correlations in the Near-Field of a Complex Supersoinc Jet Using Time-Resolved Schlieren Imaging

Abstract

In this study, we aim to characterize the dynamics and visualize the propagation of fluctuations in the near field of a complex multi-stream jet over an aft deck plate. The flow is visualized using time resolved schlieren photography (up to 400,000 frames per second) while pressure on the aft deck plate is simultaneously sampled using Kulite pressure sensors. Time series are constructed using the schlieren photographs and conditioned to reduce the effects of signal drift. The analysis is focused in several regions identified in previous studies as dynamically interesting through their high levels of pressure variance and rich spectral content. Space-Time cross correlations are utilized to visualize propagation of fluctuations from the near field to the far field, and several propagation pathways are identified. This process is repeated for band-pass filtered schlieren signals, and a case is made for the separability of near field dynamics into distinct frequency bands.