Aeroacoustic Resonance in a Deep Cavity with Grazing Flow

1. The resonant oscillation occurring in a cavity with grazing flow can produce sound with peaks at discrete frequencies.

2. The oscillation can be categorized as fluid-dynamic and fluid-resonant.

3. The fluid-dynamic oscillation is sustained by a feed-back loop consistent with the vortex in the shear layer and pressure waves from the downstream edge of the cavity.

4. The fluid-resonant oscillation is due to the Helmholtz resonance phenomenon.

5. A deep cavity can have both types of the oscillations.