碩士 / 國立成功大學 / 水利及海洋工程學系碩博士班 / 93 / The Boussinesq model has been widely used in simulating nonlinear waves transformation from deep water to shallow water in the past decade. In this thesis, the multi-layer Boussinesq model developed by Lynett and Liu (2004) is applied to investigate the phenomenon of the harbor resonance with the shape of the harbor being long and narrow. In particular, this multi-layer model exhibits accurate linear characteristics up to a kh~8 and nonlinear accuracy to kh~6 for two-layer model.
To validate this higher-order Boussinesq model, a series of numerical tests are carried out including the solitary wave propagating a long distance to ensure the stability of the model, the classical experiments conducted by Berkhoff (1982) and the experiment about the nonlinear wave transformation over submerged trapezoidal bar conducted by Beji & Battjes (1994). Our results indicated that this model could simulate the problems with open boundary very well.
For the harbor resonance, we have initially chosen the linear resonance experiment and nonlinear resonance experiment conducted by Ippen & Goda (1963) and Rogers & Mei (1978), respectively. Both of their experiments were conducted in a long and narrow harbor. However, numerical short waves are found due to the corner points at the harbor entrance, which leads to the code overflow. Similar situations are also encountered in the simulation of nonlinear harbor oscillation. Different aspect ratios of harbor geometry are then used in our simulation. In the case of linear harbor resonance, it is found that the relation between the harbor length L and the wavelength of the incident wave l is the main mechanism for whether the resonance is agitated or not. Specifically, the harbor resonance occurs as kl reaches to certain number and the change of the harbor width b seems not to play an important role. In the case of the nonlinear resonance, two findings are concluded as follows. Firstly, the distance between the incident waves to be initiated and the length of the harbor will affect the nonlinear resonance inside the harbor. This result agrees with the results presented by Rogers & Mei (1978). Secondly, the higher harmonics of incident wave will also resonate inside the harbor.
In summary, this thesis provides some results and suggestions in the simulation of the harbor resonance using higher-order Boussinesq model. However, further experiments are needed to verify our numerical findings.
| Identifer | oai:union.ndltd.org:TW/093NCKU5083017 |
| Date | January 2005 |
| Creators | Ting-Chieh Lin, 林鼎傑 |
| Contributors | Tai-Wen Hsu, Shih-Chun Hsiao, 許泰文, 蕭士俊 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 84 |
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