An Examination of Coupled Mode Theory as Applied to Underwater Sound Propagation.
Abstract
The work presented in this dissertation is a theoretical investigation of the mathematical formalism of coupled mode theory as applied to underwater sound propagation in a range dependent, ocean environment. The range dependence of an acoustic medium may be characterized by two types, range variability of the geoacoustic parameters such as sound speed and range variability of the boundary conditions. This dissertation focuses on both types of range variation and examines coupled mode theory and its various approximations with respect to the range variability of the ocean bottom. There are two approximations that arise in applications of coupled mode theory. The adiabatic approximation, which becomes valid in the limit of slight range variability of the medium, involves the neglect of the mode-mode energy coupling process. Another approximation which is inherent in the theory involves a boundary condition approximation which must be made in applications involving range variable boundaries. The adiabatic approximation is examined with respect to its validity as a function of sediment type and bottom range variability (bottom slope and radial sound speed gradient). The raypath properties of the adiabatic approximation are also examinded with respect to the multipath conversion process caused by a sloping bottom and are shown to agree with a ray theory view of the process.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 26, 1979
- Accession Number
- ADA075462
Entities
People
- Steven Ross Rutherford
Organizations
- University of Texas at Austin