Accession Number : AD0681084

Title :   ACOUSTIC RECEPTION AND FLOW NOISE CONTROL OF MOVING PIPE SENSORS.

Descriptive Note : Final rept.,

Corporate Author : RAYTHEON CO BEDFORD MASS MISSILE SYSTEMS DIV

Personal Author(s) : Chin,G. Y.

Report Date : 31 DEC 1968

Pagination or Media Count : 115

Abstract : Calculations are made for the reception properties, flow noise and equivalent flow noise of a porous pipe receiver for a range of frequencies, angles, Mach numbers, and pipe lengths. The flow noise calculations are made assuming a homogeneous turbulent boundary layer-calculations for the sea water medium are also made. Similar calculations are made for a pipe receiver having discrete holes (air medium) in finer details than that previously made in our earlier study. Experimental measurements of the directional properties of the porous pipe receiver, together with flow noise measurements made on a glider in flight, are presented - measurements compare reasonably with theoretical results. Measurements show low flow noise levels - lower than previously measured in wind tunnels and in drops from airplane. Calculated also are directivity functions of speed-tuned simple line receivers. (Author)

Descriptors :   (*ELECTROACOUSTIC TRANSDUCERS, PIPES), FLUID FLOW, NOISE, DETECTORS, ACOUSTIC PROPERTIES, MACH NUMBER, GLIDERS

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE