Investigations of the Sound Generated by Supercavity Ventilation
Final technical rept.May 2006-May 2009
BOSTON UNIV MA COLL OF ENGINEERING
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An investigation is made of the sound generated by the impingement of a ventilating jet on the interface of a ventilated supercavity. A ventilated supercavity is a gaseous envelope generated around an underwater vehicle that allows for order of magnitude increases in vehicle speeds. Hydrodynamic noise generated by the supercavity can interfere with successful vehicle deployment A principal mechanisms of noise generation is believed to be the impingement of ventilating gas jets on the gas-water cavity wall. An understanding of this interaction has been developed by analysis of a series of model problems which approximate the geometry and physical mechanisms involved in the jet-cavity interaction. The first problem is that of a spherical, gas-filled cavity in water whose surface is excited by a planar ring of axially projecting jets. The second involves a theoretical and experimental study of a jet of infinitesimal cross-section impinging at nonnal incidence on the gas-water interface. The final problem makes use of a creeping mode diffraction theory to estimate the self-noise produced by the impinging jets on the solid nose of the vehicle.
- Fluid Mechanics