Implementation of the Lamont-Doherty Geological Observatory Normal Mode/ Fast Field Model on the NUSC VAX 780/11 Computer
Abstract
A computer model that evaluates the integral solution representing the acoustic field due to a harmonic point source in a layered fluid/solid medium has been implemented on the NUSC VAX 780/11 computer. The model was developed by Dr. H. W. Kutschale of the Lamont-Doherty Geological Observatory. The version obtained by NUSC, designated 17HH, permits two computation methods. They are: (1) a normal mode method, which evaluates the field as a finite sum of propagating modes (discrete spectrum) plus a branch line integral (continuous spectrum); and (2) a fast field method, which effects a direct numerical evaluation of the integral solution via a fast Fourier transform. This report provides NUSC users with sufficient documentation for running the model to obtain predictions of sound propagation. Several test cases are presented, which illustrate various features and capabilities of the models. Keywords: Mathematical models; Branch line integral; Continuous spectrum; Contour integral; Discrete spectrum; Excitation function; Fast field model; Fast Fourier transform; Green's function; Liquid/Solid Layers; Normal mode model; Sound propgation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 18, 1984
- Accession Number
- ADA163547
Entities
People
- D. J. Thompson
Organizations
- Naval Underwater Systems Center