Pressure Fluctuations in Compressible Elliptical Cavity Flow

This experimental study determines the mean and fluctuating surface pressure distribution for a compressible elliptical cavity flow, for which the length-to-depth ratio ranges from 2.10 to 21.50 for freestream Mach numbers of 0.64, 0.70, and 0.83. The results for the mean surface pressure distribution show that the boundaries between open-, transition-, and closed-type cavities resemble those for a cylindrical or a rectangular cavity. There are significant fluctuations in the surface pressure near the trailing edge. The results for power spectral density show multiple Rossiter modes for an open-type cavity, for which the amplitude depends on the cavity geometry and the freestream Mach number. An open-type elliptical cavity generates Rossiter modes with a greater amplitude (1–3 dB) than does an open-type cylindrical cavity. An increase in the freestream Mach number results in a decrease in the fluctuating pressure coefficient. Correlation analysis shows that there is a coupling with the Rossiter modes for a deeper open-type cavity ([Formula: see text]) at a freestream Mach number of 0.83.