Accession Number : AD0654934

Title :   QUARTERLY PROGRESS REPORT FOR THE PERIOD JANUARY, FEBRUARY, AND MARCH, 1966,

Corporate Author : TEXAS UNIV AUSTIN DEFENSE RESEARCH LAB

Personal Author(s) : Mitchell,Steve K. ; Frey,Harlan G. ; Anderson,Aubrey L.

Report Date : 17 MAR 1966

Pagination or Media Count : 30

Abstract : A summary is presented of the theoretical and experimental investigation of acoustic scattering from modeled rough surfaces. Eckarts' rough scattering theory is reviewed along with the modifications of this theory with regards to the specification of a boundary condition at the surface and to a method to take into consideration shadowing at the surface by protruding anomalies at low incident grazing angles. An analytical investigation of the propagation of acoustic waves through inhomogeneous regions is presented. The applicability of the WKB approximation to the computation of propagation losses through thermoclines is examined by comparing the rigorous solution and the WKB approximation for linear index of refraction gradients. Graphs are included which allow the applicability of the WKB approximation to a particular thermocline to be determined for various gradients, frequencies and incident grazing angles. Other graphs then allow the propagation loss through the thermocline to be determined. (Author)

Descriptors :   (*ACOUSTICS, SCATTERING), WAVE PROPAGATION, ACOUSTIC PROPERTIES, SURFACE PROPERTIES, THEORY, EQUATIONS, THERMOCLINES, UNDERWATER SOUND, THEOREMS, CALIBRATION

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE