Noise from Cavitating Submerged Water Jets

Abstract

Frequency spectra of the underwater noise produced by cavitating submerged water jets were determined experimentally for nozzle diameters from 38 to 112 in., efflux velocities from 40 to 175 ft/sec, and ambient pressures up to 2 atm. When cavitation is barely incipient, the rms sound pressure varies with differences in the manner of handling the water prior to a run; this variation of sound pressure is presumably due to changes in the nuclei content of the water. When, however, the cavitation index is sufficiently small, cavitation is well advanced, and then the radiated sound is independent of the manner of treating the water. For this condition a simple relation is found to exist among the noise spectra when they are plotted as dimensionless functions of those physical quantities which determine the flow.