Accession Number : AD0781230

Title :   GRASS: A Digital-Computer Ray-Tracing and Transmission-Loss-Prediction System. Volume 1. Overall Description,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Cornyn,John J.

Report Date : 21 DEC 1973

Pagination or Media Count : 75

Abstract : GRASS (Germinating Ray-Acoustics Simulation System) is a set of linked digital computer programs (Fortran), or modules. These modules: (1) convert salinity, temperature, and depth (STD) data to sound-speed profiles; (2) interpolate and extrapolate the sound-speed field; (3) generate Calcomp or Gerber plots of the sound-speed profiles; (4) generate contour and three-dimensional isometric plots of the sound-speed field; (5) trace rays and calculate intensities; (6) generate ray diagrams; and (7) construct plots of the calculated transmission loss versus range. The system can handle multiple profiles and a linear-segmented bottom profile. It is presently running on a CDC 3800. This report, the first of a two-volume set, includes an overview of each module, outlines the methods used in the calculations, provides the results of some test cases, makes some recommendations for improvement, and briefly compares ray and normal-mode theories. (Author)

Descriptors :   *Underwater sound, *Computer programming, *Sonar signals, Sound transmission, Ray tracing, Transmission loss, Wave equations, Instruction manuals, FORTRAN, Numerical analysis

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE