EFFECTIVE ACOUSTIC MODELLING OF SEABEDS WITH GEO-ACOUSTIC GRADIENTS

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Authors
  1. Li, J-F.
  2. Hodgson, M.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);British Columbia Univ, Vancouver BC (CAN) Office of Research Services
Abstract
The reflection coefficient is a useful and informative quantity. This work considers the plane-wave reflection from seabeds with geo-acoustic gradients. A literature review has been done of the available literature on the subject of modelling seabeds with varying density and sound speed. A three layer-model consisting of water, sediment and substrate is used for modelling reflection of a plane wave from a sediment layer with continuously varying density and sound-speed profiles. Absorption losses in the sediment and substrate are taken into account. Exact solutions of the Helmholtz equation in an inhomogeneous layer are used to obtain expressions for the plane-wave reflection coefficient, which enable us to do a sensitivity analysis of the seabed properties to the parameters, including frequency, absorption losses of the media, the gradient of linear sound-speed profile, density and the form of sound-speed profiles. Numerical results are given to show the effects of parameters of the seabed on the reflection coefficient.
Keywords
Seabeds;Shear waves;Density profile;Plane waves;Reflection loss;Geoacoustics
Report Number
DREA-CR-98-404 — Contractor Report
Date of publication
01 Oct 1997
Number of Pages
63
DSTKIM No
98-01874
CANDIS No
508513
Format(s):
Hardcopy;Document Image stored on Optical Disk

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