碩士 / 國立臺灣海洋大學 / 河海工程學系 / 103 / This study aims to provide simulations on dynamic characteristics for an auxiliary floating platform being used to monitoring ocean energy converters in national ocean energy testing fields. Two typical floating platforms, including a ship and a buoy-shaped, were proposed. The numerical simulations adopted frequency-domain BEM potential flow model WAMIT. With considerations of wave excitation force and the radiation force, kinematic behaviors (Response amplitude operator, RAO) and drift force caused by different wave periods and directions were discussed. Effects of different loads and counterweights on RAO and drift forces were analyzed and then extended to the effects of wave direction and depth. The drift forces were calculated using far-field method for further adoption on mooring design.
Numerical results demonstrate that in all cases resonance periods of 2-2.5s caused by different loads and counterweights were less than wave periods of 4-10s in ocean energy testing fields. In case of heavier total weight or lower center of gravity, horizontal motion amplitude and peak mean drift force became smaller. The resonance periods slightly shift to longer values for heavier weight or higher center of gravity. There is no significant difference in the normal incident waves for both types of floating platforms. But for lateral-incident waves on the ship-shaped platform, there were significantly larger drift force peaks. Finally, comparing those at water depth of 30m with those at water depths deeper than 200m, it is seen that wave periods longer than 7s could significant increase the horizontal displacements and further up to 1.5 times in 15s.
| Identifer | oai:union.ndltd.org:TW/103NTOU5192012 |
| Date | January 2015 |
| Creators | Chen, Jen-Yu, 陳人瑜 |
| Contributors | Tzang, Shiaw-Yih, 臧效義 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 98 |
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