The Coupled-Mode Method for Transmission Loss Calculation in a Range- Dependent Oceanic Environment
Abstract
This report presents the coupled normal mode model to calculate the propagation loss of low-frequency acoustic signals in a range-dependent shallow ocean. It also derives the equations to include the effects of the continuous spectrum and the environmental attentuation using the first and second order perturbation terms to the solution of the real eigenequation. The bottom is assumed to have no shear effects and an axially symmetric cylindrical coordinate system is used. Therefore, no bearing dependence of the environment is also assumed in this model. It has been found that the first order perturbation term is purely imaginary, providing the imagery part of the eigenvalues and eigenfunctions. The range-dependent environment is divided into a suitable number of range-independent segments, and the respective modes are calculated in order to couple them to account for the interchange of energy and heat to adjacent modes. A simple environment is used to display the importance of mode coupling in a range-dependent ocean environment. (edc)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 27, 1989
- Accession Number
- ADA219434
Entities
People
- Juan I. Arvelo Jr.
Organizations
- Naval Surface Warfare Center