Asymptotic Analysis of Ocean Bottom Reflected Acoustic Fields.
Abstract
It has been observed in the deep ocean that the total acoustic field generated by a harmonic point source placed in the water column near the ocean bottom is characterized by strong interference between the field reflected off the bottom and the direct field through the water column. The amplitude of this total field thus shows a distinct spatial interference pattern with horizontal range. This thesis involves the analytic computation of the bottom reflected acoustic field using assumed geoacoustic models in order to understand the mechanism of propagating waves in ocean bottom sediments. The analytic results obtained are based on asymptotic approximations valid in the far field and characterize different types of rays which contribute to the total reflected field. Therefore, they provide physical insight into the understanding of energy partitioning in the sediments. The methods developed in this thesis are applied both to the examination of the fields generated by various canonical geoacoustic models and to actual experimental pressure field measurements made by Frisk and his co-workers. Extensive tests to determine which major ray paths contribute to the total reflected field are performed throughout horizontal range as well as an investigation of the effects of geoacoustic parameters on such rays.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1984
- Accession Number
- ADA144449
Entities
People
- H. Kawahara
Organizations
- Woods Hole Oceanographic Institution