碩士 / 國立成功大學 / 水利及海洋工程學系 / 106 / Co-exist of wind wave and swell is common in the real ocean. In frequency domain, this crossing sea is expressed by a bimodal spectrum. This study works on the bimodal analysis for Taiwanese Waters. It is found the occurrence probability of bimodal is only 8.8%. The significant wave height in bimodal sea state 1.66m is 15% lower than annual average wave height. In addition, bimodal has higher occurrence probability in non-typhoon condition. To formulate the bimodal spectra, four models presented by previous researchers are evaluated. They are Six-Parameters Spectrum Model, Guedes Soares Spectrum Model, Torsethaugen Spectrum Model and Mackay Spectrum Model. The candidate models are fitting to real bimodal spectra. The best model is the Six-Parameters Spectrum Model according to several evaluation parameters. However, it is found the bimodal spectrum deformed to uni-modal when swell energy above 50% of wind wave energy and the frequency difference less than 0.09 Hz. This is unreasonable. This study proposed a new model that is composed of a Gaussian function and a JONSWAP-Glenn model. This new model has been verified by field data and proofed to have better performance. The deformation rate reduces from 6% to 3% by using the proposed model. This study proposed a useful bimodal spectrum model for future application.
| Identifer | oai:union.ndltd.org:TW/106NCKU5083035 |
| Date | January 2018 |
| Creators | Hsiang-YuWu, 吳祥煜 |
| Contributors | Dong-Jiing Doong, 董東璟 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 76 |
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