A Shallow Water Range Dependent Acoustic Propagation Problem with a Stepwise Coupled Mode Solution

Abstract

A particular shallow water range dependent environment was chosen and the stepwise coupled mode model COUPLE was applied. The problem consisted of a refracting water layer overlying an isospeed liquid sediment. The water depth varied between 120 m and 210 m over a range of 50 km. The calculations were done at 50 and 300HZ. The main range dependent effect considered was the redistribution of energy due to forward and backscatter caused by both large and small scale bathymetic changes. The large scale changes, that evolve slowly with range, produced a smooth transition of energy between different sized sets of locally propagating modes. The more rapid, and small scale, changes caused a pronounced energy loss due to forward scattering into highly attenuated high angle modes. The effects of backscatter were negligible. The results are compared in this paper of IFD/PE and, in a subsequent paper, with other parabolic equation models.

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Document Details

Document Type
Technical Report
Publication Date
Sep 29, 1987
Accession Number
ADA227791

Entities

People

  • James M. Syck
  • Richard B. Evans

Organizations

  • Naval Underwater Systems Center

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Propagation
  • Backscattering
  • Classification
  • Defense Systems
  • Environment
  • Equations
  • Forward Scattering
  • Frequency
  • High Angles
  • Losses
  • Mathematics
  • Roughness
  • Scattering
  • Sediments
  • Shallow Water
  • Transitions
  • Water

Readers

  • Acoustical Oceanography.
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Regression Analysis.