碩士 / 國立中山大學 / 海下技術研究所 / 91 / Acoustic point-source reflection from an unperturbed seabed with a continuously varying density and sound speed profile in a fluid-like sediment layer overlying an elastic basement is considered in this paper. This fundamental problem has illuminated many interesting phenomena about the effects of sediment stratification on acoustic wave interactions with the seabeds.
The analysis employs the analytical solutions for the Helmholtz equation in the sediment layer, in which the density and the sound speed are, respectively, described by three kinds of geological models. The results have demonstrated that the effects of sediment stratifacation are confined in a region in range, where the reflection field is dominated by the reflected ray bundles containing ray components with the grazing angles which are neither too steep nor too shallow.
The effects of many other factors, such as frequency, sediment thickness, basement elasticity, on the reflection fields are investigated, in particular, the interface wave component may become important in the region close to the seabed, if the sediment thickness is relatively thin in comparison with the acoustic wave length.
| Identifer | oai:union.ndltd.org:TW/091NSYS5637006 |
| Date | January 2003 |
| Creators | Chung-Ray Chu, 朱崇銳 |
| Contributors | Jin-Yuan Liu, 劉金源 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 81 |
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