Accession Number : AD0715773

Title :   Analyses of Towed Hydrophone Flow Noise.

Descriptive Note : Technical rept.,

Corporate Author : WOODS HOLE OCEANOGRAPHIC INSTITUTION MASS

Personal Author(s) : Beckerle,J. C. ; Orange,A. ; Woznick,B.

Report Date : NOV 1970

Pagination or Media Count : 34

Abstract : Data have been obtained on the noise field observed at hydrophones being towed at speeds between 2 and 12 knots. The data were digitized and subjected to auto and cross spectral analysis. The spectra of the noise show strong peaks below approximately 100 cps and the total power and width of the peak as a strong function of ship speed. The coherency of signals at two hydrophones is low in the vicinity of the peak, indicating that this noise field is not due to water-borne ture sound. At low ship speeds, the noise in the 200 - 500 cps band is shown to be coherent, but at the higher speeds, this coherence is lost. The noise power in a narrow frequency band at high ship speeds is shown to vary rapidly with time. (Author)

Descriptors :   (*UNDERWATER SOUND, BOUNDARY LAYER), (*HYDROPHONES, NOISE ANALYZERS), SPECTRUM ANALYZERS, SONAR ARRAYS, PROPELLER NOISE, MARINE BIOLOGICAL NOISE, UNDERWATER SOUND SIGNALS

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE