碩士 / 國立臺灣大學 / 工程科學與海洋工程學系 / 91 / The subject of this paper is to study the reflection coefficient measurement of material in water. Using the criteria of ASTM, which is a standard procedure for the material impedance measurement in air, an impedance tube that filled of water was designed. Using the two hydrophones method and phase shift concept, the reflection coefficient has be derived theoretically. The reflection coefficient of steel and some absorption materials were measured in this designed impedance tube. Random noise of frequency between 1kHz to 8kHz was used as the sound source. During the experimenter, the design of the tube has been modified twice, firstly, its length its been increased, and secondly, a PVC tube of smaller diameter was inserted into the steel tube to reduce the wall effect so the plane wave assumption in the water can be matched. Final results show that more consistence data can obtained offer the modification.
| Identifer | oai:union.ndltd.org:TW/091NTU00345037 |
| Date | January 2003 |
| Creators | CHEN LI-BANG, 陳理邦 |
| Contributors | Tse Chuan- Cheung, 謝傳璋 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 52 |
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