Accession Number : AD0721432

Title :   Measurement of Noise on an Underwater Towed Body,

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

Personal Author(s) : Nishi,R. Y. ; Stockhausen,J. H. ; Evensen,E.

Report Date : 17 NOV 1969

Pagination or Media Count : 8

Abstract : Noise has been measured on a streamlined body of revolution towed by a hydrofoil craft at speeds up to 30kt. The body was instrumented with accelerometers, flush-mounted hydrophones in the wall, and cylindrical hydrophones in the interior of the body. Towing was conducted with different lengths of cable. The noise in the body was found to result from body-wall vibrations, from farfield radiated noise sources, and from flow noise caused by pressure fluctuations in the turbulent boundary layer. Wall vibrations were found to be caused by cable vibrations, cavitation, and other flow-induced mechanisms. The pressure distribution along the towed body and thickness of the turbulent boundary layer have been calculated and are also presented to aid in the interpretation of the results. (Author)

Descriptors :   (*UNDERWATER SOUND, NOISE), (*NOISE, TOWED BODIES), BOUNDARY LAYER, VIBRATION, TEST METHODS, TEST EQUIPMENT, BOUNDARY LAYER TRANSITION, PRESSURE, DRAG, CANADA

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE