Accession Number : AD0730702

Title :   Application of Modified Ray Theory to Underwater Sound Propagation.

Descriptive Note : Technical rept.,

Corporate Author : WOODS HOLE OCEANOGRAPHIC INSTITUTION MASS

Personal Author(s) : Murphy,E. L. ; Davis,J. A. ; Doutt,J. A.

Report Date : JUL 1971

Pagination or Media Count : 21

Abstract : At frequencies of a few hundred Hertz or less, diffraction effects can be significant for sound propagation in the oceans. A modified ray representation for some of these effects has recently been developed. The method applies to propagation through regions of local sound-velocity maximum, and for rays reflected or refracted away from a boundary region with velocity profile monotonically decreasing away from the boundary. In this paper, velocity profiles are considered, varying only with depth, composed of nearly linear and nearly parabolic segments joined with continuous derivative. In this way, modified ray analysis covers a wide class of realistic profiles pertinent to underwater sound propagation. Modified ray analysis is most conveniently formulated as wavelength-dependent 'ray displacement' and 'leakage' phenomena. Ranges for displaced rays (at given receiver depth) versus ray parameter (angle at source) are presented for unbounded examples and for profiles bounded by pressure release or rigid surfaces. Leakage coefficients are included for the unbounded examples. Unlike ordinary ray representations, modified rays are not sensitive to small changes in profile. (Author)

Descriptors :   (*UNDERWATER SOUND, SOUND TRANSMISSION), DIFFRACTION, PROPAGATION, VELOCITY, BOUNDARY LAYER, WAVE FUNCTIONS

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE