Examination of three-dimensional (3-D) effects on sound propagation through mesoscale features using 3-D coupled mode theory
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Authors
Binhlam, Jacqueline M.
Subjects
Underwater sound propagation modeling
Advisors
Chiu, Ching-Sang
Ehret, Laura L.
Date of Issue
1992-06
Date
June 1992
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
A study of the three dimensional (3-D) effects of mesoscale variability on underwater sound propagation is conducted by interfacing the Chiu-Ehret 3-D acoustic coupled mode (CM) model with a forecasted sound speed field generated by the Harvard Open Ocean Model (HOOM). This research concentrates on the sensitivity of the acoustic wave field to source depth and location with respect to a core ring in the Gulf Stream system for a 50 Hz sound source. The inclusion of the exact 3-D physics in acoustics modeling requires substantial computer resources. For this reason, it is very desirable to determine when the simpler adiabatic or Nx2-D approximations may be used. To achieve this goal, "exact" 3-D acoustic coupled mode model calculations are compared to results from the adiabatic approximation and the Nx2-D approximation in terms of transmission loss and phases and amplitudes of individual mode modulation envelopes. The results show that the accuracy of the adiabatic and Nx2-D approximations depend strongly on the radial and transverse sound speed gradients along the track and the acoustic quality considered.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
68 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.