Accession Number : ADA118685

Title :   Propeller Cavitation Noise Investigations in a Free-Field Environment.

Descriptive Note : Technical memo.,

Corporate Author : DEFENCE RESEARCH ESTABLISHMENT ATLANTIC DARTMOUTH (NOVA SCOTIA)

Personal Author(s) : Leggat,L John

PDF Url : ADA118685

Report Date : Jun 1982

Pagination or Media Count : 37

Abstract : Cavitation is the dominant source of noise for cavitating propellers. It is generally agreed that the growth and collapse of cavitation bubbles creates a monopole acoustic source mechanism, which radiates sound in an omnidirectional pattern from the oscillating bubble. Hydrodynamic flows about propellers produce other types of cavitation besides bubble cavitation. Vortex cavitation occurs in the concentrated tip and hub vortices, and sheet cavitation can occur at the propeller blade leading edge. Each of these types of cavitation may have different acoustic source strengths and source spectra. A propeller drive apparatus has been built at the Acoustics Barge at the Defence Research Establishment Atlantic. The fully instrumented barge is located in Bedford Basin, a large soft-bottom salt-water body of water near Halifax. A stationary propeller drive pod and near and far-field hydrophones are fixed to and suspended from the barge. Propellers designed to produce various types of cavitation have been tested in this facility.

Descriptors :   *Cavitation noise, Marine propellers, Bubbles, Free field, Acoustic ranges, Collapse, Radiated noise, Propeller noise, Omnidirectional, Hydrodynamic control surfaces, Canada

Subject Categories : Marine Engineering
      Test Facilities, Equipment and Methods
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE