INVESTIGATION OF SURFACE PRESSURE FLUCTUATIONS USING PRESSURE SENSITIVE FILM

This study investigates the dynamics of oblique shock wave interactions impinging on a flat plate within the Purdue University Research and Innovation Optical Testing (RIOT) Tunnel, employing novel pressure sensitive film (PSF) to visualize and quantify global surface pressure distributions. Complementary diagnostics, including static and dynamic pressure sensors and high-speed imaging, were used to provide a comprehensive analysis of the shocks spatial and temporal behavior.
Experimental campaigns were conducted in a supersonic wind tunnel equipped with a rated Mach 1.86 nozzle, characterizing the nominal conditions required for PSF application. Test campaigns spanned a range of stagnation pressures, revealing the dependence of shock-induced pressure distributions on flow conditions. Calibration using the Stern-Volmer relationship provided robust intensity-pressure correlations, incorporating temperature corrections to address quenching effects. Spectral analysis of pressure measurements identified low- and mid-frequency fluctuations associated with turbulent boundary layers and shock oscillations.