碩士 / 國立成功大學 / 水利及海洋工程學系碩博士班 / 95 / We observe the front wave change from the quiet water state to steady wave motion state, when the wave train which are created by wave maker are delivered to the lower reaches of water flume. There is the non-linear and unstable wave between quiet water state and steady state. We call it wave front of wave train. The phenomenon of wave front shows the wave modulation, and finally becomes The phenomenon of wave group looking like real sea level. Due to understanding the characteristic of wave front, we can continue to discuss the wave group at field ocean or the characteristic of stormy waves which is created from quiet water state. We will use the experimental data of non-linear wave front to illustrate the evolution of it on the research.
The experiments were carried out in a super wave flume whose length is 300m, and width is 5m, and height is 5.2m at Tainan Hydraulics Laboratory in National Cheng-Kung University. We analyse the development of non-linear wave front that are derived from two typical non-linear wave train. The two typical non-linear wave train are regular wave and Bichromatic waves. Because the analysis of used Fourier analysis only can show the change in whole frequency, we decide to use wavelet analysis that have analytical ability of frequency and time domain, and also have good ability to analyse Bichromatic waves. We discuss the development of wave front that are derived from deep-water non-linear wave train by using it.
From the result of the wavelet analysis, both regular wave and Bichromatic wave clearly show the change of peak frequency at any time. In wavelet spectrum, the peak frequency of high amplitude is taller than steady section. We also discuss the change of wave steepness and phase velocity.
Contrasted to wavelet spectrum, we find that the power of slow phase velocity become more concentrated. After wave front separate from leading wave, the frequency of phase velocity and the wave's steepness of the biggest wave also turn into stable value.
| Identifer | oai:union.ndltd.org:TW/095NCKU5083055 |
| Date | January 2007 |
| Creators | Chin-Yung Liu, 劉晉湧 |
| Contributors | Hwung-Hweng Hwung, 黃煌煇 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 91 |
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