Acoustic Scattering from Sand Dollars (Dendraster excentricus): Modeling as High Aspect Ratio Oblate Objects and Comparison to Experiment

Abstract

Benthic shells can contribute greatly to the scattering variability of the ocean bottom, particularly at low grazing angles. Among the effects of shell aggregates are increased scattering strength and potential subcritical angle penetration of the seafloor. Sand dollars (Dendraster excentricus) occur commonly in the ocean and have been shown to be significant scatters of sound. In order to understand more fully the scattering mechanisms of these organisms, the scattering from individual sand dollars was studied using several methods. The finite element method, a numerical technique for approximating the solutions to partial differential equations and integral equations, was used to model the scattering from an individual sand dollar as well.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 2008
Accession Number
ADA541123

Entities

People

  • Gregory C. Dietzen

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Air Platforms
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Acoustic Scattering
  • Acoustic Waves
  • Acoustics
  • Backscattering
  • Boundary Value Problems
  • Coordinate Systems
  • Differential Equations
  • Diffraction
  • Electromagnetic Scattering
  • Far Field
  • Finite Element Analysis
  • Geometry
  • Helmholtz Equations
  • Partial Differential Equations
  • Seabed
  • Underwater Acoustics
  • X-Ray Computed Tomography

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Calculus or Mathematical Analysis
  • Marine Ecotoxicology