An experimental study of pressure fluctuations generated by an open shallow cavity performed using joint time-frequency techniques of data analysis

An experimental study of the flow over a single open shallow cavity is reported. Pressure fluctuations were measured using two cavity models at free-stream Mach numbers 0.3, 0.5, and 0.6. At certain conditions, resonance of acoustic waves inside cavity with disturbances in the shear layer over cavity was observed. Pressure fluctuation characteristics were analysed using Fourier, wavelet, and Hilbert — Huang transforms. Those methods have allowed us to accurately examine the transition of the flow over cavity into resonant state.