Fast Pressure-Sensitive Paint Imaging Of Three-Dimensional Non-Stationary Shock Oscillations In A Mach-5 Intake With Synchronised Schlieren Support
M.T. Gurbuz(1), E.J. Nunn(2), O. Ozer(3), K.L. Smith(4), M.K. Quinn(5)
1, 3, 4,
5: Dept. of Mechanical and Aerospace Engineering, The University of Manchester, UK
2: Dept. of Chemistry, The University of Manchester, UK
DOI:
Non-stationary shock oscillations in high-speed intakes are inherently unsteady and can exhibit three-dimensional behaviour, even in nominally planar geometries. Conventional optical diagnostics, such as schlieren, provide valuable qualitative information but cannot directly resolve the corresponding surface-pressure field. In this study, fast pressure-sensitive paint (fast-PSP) is applied to investigate shock oscillations in a Mach 5 planar intake operating at a throttling ratio of 28%. Time-resolved surface-pressure measurements were acquired at 20 kHz and synchronised with high-speed schlieren imaging, enabling direct comparison between the flow-field shock structure and its surface-pressure footprint. Spectral and modal analyses reveal dominant oscillation frequencies near 290 Hz, consistent with previous schlieren measurements of the same intake. The results also demonstrate clear spanwise asymmetry and spatial variations in oscillation behaviour across the ramp surface. These findings highlight the capability of fast-PSP to capture three-dimensional shock dynamics that are inaccessible to conventional line-of-sight optical diagnostics.
