Ray Representation of Sound Scattering by Weakly Scattering Deformed Fluid Cylinders; Simple Physics and Application to Zooplankton.

Abstract

Data indicate that certain important types of marine organisms behave acoustically like weakly scattering fluid bodies (i.e., their material properties appear fluidlike and similar to those of the surrounding fluid medium). Use of this boundary condition, along with certain assumptions, allows reduction of what is a very complex scattering problem to a relatively simple, approximate ray-based solution. Because of the diversity of this problem, the formulation is presented in two articles: this first one in which the basic physics of the scattering process is described where the incident sound wave is nearly normally incident upon a single target (i.e., the region in which the scattering amplitude is typically at or near a maximum value for the individual) and the second one Stanton et at., J. Acoust. Soc. Am. 94, 3463-3472 (1993) where the formulation is heuristically extended to all angles of incidence and then statistically averaged over a range of angles and target sizes to produce a collective echo involving an aggregation of randomly oriented different sized scatterers.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1993
Accession Number
ADA279106

Entities

People

  • Clarence S. Clay
  • Dezhang Chu
  • Timothy K. Stanton

Organizations

  • Woods Hole Oceanographic Institution

Tags

DTIC Thesaurus Topics

  • Acoustic Propagation
  • Acoustic Waves
  • Acoustics
  • Amplitude
  • Aquatic Organisms
  • Backscattering
  • Elastic Waves
  • Frequency
  • Fresnel Integrals
  • Geometry
  • Orientation (Direction)
  • Physics
  • Plane Waves
  • Scattering
  • Sound Waves
  • Waves
  • Zooplankton

Fields of Study

  • Physics

Readers

  • Acoustical Oceanography.
  • Fluid Dynamics.
  • Theoretical Analysis.