ALTERNATING DIRECTION EXPLICIT-IMPLICIT COMPUTATIONAL METHOD APPLIED TO LOW-FREQUENCY UNDERWATER SOUND PROPAGATION

Abstract

A new sonar interpretation technique for range determination under conditions in which the usual approximate methods are inadequate. A computer solution of the two-dimensional undamped linearized wave equations is found by using an interlacing explicit-implicit scheme. In the computation, the entire two-dimensional field is found as a function of time. The examples considered involve wave propagation in a homogeneous shallow-water channel where the effect of superposition of discrete spectra produces characteristic modal patterns. The spatial sound pressure fluctuations are represented as plot-density variations along the two-dimensional channel. Examples of discrete propagated modes as well as evanescent modes are presented. The size of the field that can be presented is limited by the size, accuracy, and speed of the computer. The method is programmed in FORTRAN IV for use on the IBM-7040-7044 computer with the S-C 4060 microfilm recorder. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Jul 01, 1968
Accession Number
AD0672588

Entities

People

  • Malcolm Smith
  • R. H. Mayall
  • S. V. Huber

Organizations

  • RAND Corporation

Tags

Communities of Interest

  • C4I

DTIC Thesaurus Topics

  • Amplitude
  • Boundaries
  • Computations
  • Computer Programs
  • Computers
  • Coordinate Systems
  • Difference Equations
  • Differential Equations
  • Equations
  • Frequency
  • Grids
  • Interlacing
  • Sound Pressure
  • Steady State
  • Two Dimensional
  • Wave Equations
  • Waves

Fields of Study

  • Physics

Readers

  • Acoustical Oceanography.
  • Computer Science/Computer Engineering/Data Science/Digital Signal Processing.
  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)