Discrete frequency acoustics correlation for rectangular cavities exposed to high speed flows

Engineers and scientists at the Arnold Engineering Development Center (AEDC), National Aeronautics and Space Administration (NASA), Wright-Patterson Air Force Base, the Royal Aircraft Establishment, and others have been studying flow-induced pressure oscillations in cavities (for more than four decades) to establish a basis for an analytical frequency prediction technique. In the present study, a variable-depth rectangular cavity was exposed to a tangential flow over the cavity in the Mach number range from 0.6 to 5.0. Spectral data were studied at various locations within the cavity to gain insight on broadband and resonant response characteristics of the cavity. Based on the data, the Rossiter scheme for predicting resonant frequencies was modified and extended to the higher Mach number of this study to enhance the prediction technique. Potential problems arise when the assumptions used in the cavity flow model are invalidated by physical phenomena such as a coupling of the cavity multidimensional modes and cavity edge tones.