Scattering of Evanescent Acoustic Waves by Regular and Irregular Objects

Abstract

Sound incident on the sea bottom at small grazing angles can produce acoustical evanescent waves in the sediment. The objective of this project was to describe the scattering by regular and irregular objects illuminated by acoustical evanescent waves in a simulated sediment. The theoretical developments were tested with laboratory scale experiments using a unique facility. The observables of interest in the scattering included (but were not limited to): (1) the scattering amplitude as a function of target depth and orientation; (2) the timing of the scattered signals; (3) the frequency dependence of the scattering. Objects investigated included objects having narrow resonances. The results should be helpful in selecting filters to optimize the signal-to-reverberation-ratio for targets buried in real environments and to reduce the rate of false alarms.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 2006
Accession Number
ADA459639

Entities

People

  • Philip L Marston

Organizations

  • Washington State University

Tags

Communities of Interest

  • Air Platforms
  • Sensors

DTIC Thesaurus Topics

  • Acoustic Scattering
  • Acoustic Waves
  • Acoustics
  • Amplitude
  • Angle Of Incidence
  • Detection
  • Detectors
  • Diffraction
  • Evanescent Waves
  • Free Field
  • Frequency
  • Geometry
  • Grazing
  • Grazing Angles
  • Scattering
  • Seabed
  • Waves

Fields of Study

  • Physics

Readers

  • Geotechnical Engineering.
  • Sensor Fusion and Tracking Systems.
  • Spectroscopy.