碩士 / 國立交通大學 / 環境工程系所 / 100 / A general mathematical model is developed for describing head fluctuations in an aquifer of oceanic islands subject to a dual tide effect. The upper boundary condition of the aquifer is represented by an equation combining the simplified free surface equation with a leakage term. Such an equation is considered as a general expression representing the upper boundary condition of confined, unconfined, or leaky confined aquifers. The closed-form solution of the model represented by two series terms is then developed by the direct Fourier method and finite Fourier sine transform. One of the series can further reduce to a closed-form expression by means of contour integral and residue theorem. Under the condition that the width of the island is very large, this solution can give the predicted head almost the same as that of the solution for an aquifer subject to a single tide effect. It is found that the presence of an upper aquitard may result in significant vertical flow in the lower confined aquifer even if the aquitard permeability is low. The amplitude coefficient and phase shift predicted from the solution subject to the dual tide effect agree well with the ones estimated from 57-day head fluctuation data observed at Garden Island, Australia.
| Identifer | oai:union.ndltd.org:TW/100NCTU5515010 |
| Date | January 2011 |
| Creators | Chang, Chia-Hao, 張家豪 |
| Contributors | Yeh, Hund-Der, 葉弘德 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 36 |
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