Development of a High Resolution 3-D circulation Model for the Assessment of Tidal Current Energy in Peng-Hu

• Main Authors: Yu-chun Chang, 張瑀峻
• Other Authors: Hwa Chien
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/08678866702552945304

碩士 === 國立中央大學 === 水文與海洋科學研究所 === 100 === Tidal power is a clear and constant renewable ocean energy that can be predicted accurately. With the rapid development of shallow water turbine technologies in the commercial market, the uncertainties of the investment in terms of cost-benefit assessment can be reduced. The tidal current energy conversion is considered as one of the favorable alternative in Taiwan’s energy policy. One of the crucial issues is the impacts that may be brought by the installation of turbines. As the kinetic energy is uptaken, the follow field will change and hence the transportation of nutrients, plankton and lava will altered, which leads to the direct impact of ocean ecosystem. The aim of present study is to setup a high-resolution 3-D ocean circulation model that is capable to simulate the tidal current at curvy coastline in Peng-Hu Archipelago. The numerical model system is first validated using field measured datasets. From the simulation results, it is found that the Hou-Men Channel and western Si-Yu sea area have the greatest energy potential in Peng-Hu. It is worthy to noted that the processes of tidal dynamic in the inner-bay of Peng-Hu Archipelago behave similar to a lagoon with two narrow open ends, where the effects of phase lags of major constituents is limited. The almost synchronized tidal current flow into the inner-bay from the north and south ends can be identified during flood tide and vice versa. Concerning to the approaches to simulate the effects of the installation of tidal energy conversion units, this study adopted the method of modifying the bottom drag coefficient to simulate the flow field change incurred by installing difference turbine of various capacities. Furthmore, the discussions on the change of current fields in the vicinity of installations as well as the change of water body exchange rate in the inner-bay with respect to various turbine capacities are carried out. In the Hou-Men Channel case, the location of strong current stream will move northward due to the installation of turbines, and the velocity increases in the south channel. In western Si-Yu sea area, the location of strong current stream moves westward. From the results, both Hou-Men Channel and western Si-Yu sea area entertained more severe impacts of the shifting of strong stream locations as the capacity of turbine increased. This study also compares the variation of the rates of water body exchanged at different sites through the tracer simulated experiments. For example, the setup a 30kW idealized turbine in Hou-Men Channel will inccur, the tracer spearding area reduced by 16% compared to original case. In western Si-Yu sea area, there seems no significant altering of tracer spreading with respect to different capcities of turbine.