Accession Number : AD0737629

Title :   A Normal Mode Computer Program for Calculating Sound Propagation in Shallow Water with an Arbitrary Velocity Profile.

Descriptive Note : Final rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Newman,Alfred V. ; Ingenito,Frank

Report Date : JAN 1972

Pagination or Media Count : 70

Abstract : A computer program has been written in FORTRAN 3400/3600/3800 which solves the Z dependent part of the Helmholtz equation for a two fluid shallow water model by means of a finite difference technique. Sound speed profiles for the model are entered as discrete sets of points. The first fluid is subdivided into N incremental layers to permit the use of the finite difference equations. A linear interpolation is performed between the profile depths and the depths at which the incremental layers are defined to give sound speeds for the latter. The boundary conditions for continuity of acoustic pressure and the vertical particle velocity are matched at the interface between the two fluids. The effect on each normal mode amplitude in the first fluid due to an assumed small absorption in the second fluid is found. (Author)

Descriptors :   (*SOUND TRANSMISSION, SHALLOW WATER), (*UNDERWATER SOUND, *COMPUTER PROGRAMS), ATTENUATION, DIFFERENCE EQUATIONS, BOUNDARY LAYER, BOUNDARY VALUE PROBLEMS

Subject Categories : Computer Programming and Software
      Acoustic Detection and Detectors
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE