Progress of research on noise induced by compressible flow over cavities

The cavity is commonly employed in designing an aircraft. Nevertheless, the cavity flow, especially under high-speed conditions, is usually an important noise source, restricting the performance of the aircraft. The research progress on the cavity noise is summarized, including characteristics of the cavity oscillation, generation of the aeroacoustic noise, parameters which influence the cavity flow, and control of the cavity noise. The generation and propagation of the noise induced by the compressible flow over cavities are analyzed based on the characteristics of the unsteady cavity flow. Parameters that determine the cavity flow and noise are classified according to flow conditions, cavity geometry and structural vibrations. Furthermore, effects of these parameters on the cavity noise are considered, and the passive and active control techniques are summarized. Finally, challenges and future directions of researches on the cavity noise are outlined.