博士 / 國立臺灣大學 / 土木工程學研究所 / 106 / In the literatures, saltwater intrusion has been studied for long time. However, since the lack of boundary conditions at saltwater intrusion areas, or considering freshwater-saltwater interfaces as solid boundary and assuming there is no stagnation point for saltwater intrusion, those models are insufficient for explanations of real world. First, we clarified Gheben-Herzberg equation, and Helmholtz theory is applied to sparate the irrotational potential flow and rotational viscous boundary layer flow. Last, Brinkman equation is applied to calculate boundary layer. The study found phenomena that (1) freshwater-saltwater interfaces as fluid boundary; (2) saltwater could reflux because of the boundary layer effect; (3) there is stagnation point for saltwater intrusion. This allows us to understand the mechanism of saltwater intrusion which includes the fluctuations of boundary layer effect. On the other hand, we propose the conceptual of saltwater base flow, using the law of conservation of matter, the amount of saltwater injection must equal to the amount of fresh water outflow. The concept of saltwater base flow can provide simulated boundary condition to handle the correct flow condition at simulated area when the real boundary condition is absent. Utilizing mathematical formulation, boundary layer effect and the base flow of saltwater to construct the saltwater intrusion mechanisms.
In the earlier stage of the study, we propose a new idea for two-dimensional seawater intrusion. In order to utilize the theory, we extend the study to three-dimension and provide a more reasonable method. First, we plan to construct the seawater intrusion mechanisms by interpolating and deriving the boundary conditions of saltwater base flow. Moreover, we extend the groundwater model for irregular boundary (Wang(2013)) to simulate seawater intrusion mechanisms. By using mathematical theories, boundary effect, conceptual of seawater base flow and intrusion mechanism The calculation of groundwater seawater intrusion in Pingtung Plain was successfully completed.
| Identifer | oai:union.ndltd.org:TW/106NTU05015017 |
| Date | January 2018 |
| Creators | Cheng-Wei Chang, 張正緯 |
| Contributors | , 黃良雄, 俞維昇 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 80 |
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