Simulation Studies of the Pumping Rate in Unconfined Aquifers by Finite Element Method
Date Issued
2004
Date
2004
Author(s)
Tung, Jen
DOI
zh-TW
Abstract
Due to the rapid development of numerical analysis and computer, scholars employ mathematical model to simulate the groundwater flow, a complex physical phenomenon. It is used to discuss the flow in a two-dimensional unconfined aquifer in the horizontal (x-y) plane. The governing equation is a nonlinear partial differential one, and the vertical section involves the phenomenon of unsaturated porous media flow which has a more complex phenomenon and more uncertain parameters. Therefore, the purpose of the article is to reduce the estimate of parameters in an unsaturated porous media flow, and not to quote some theories of an unconfined aquifer. We calculate the total volume of water released from storage in the aquifer per unit time due to the elastic storage and the actual drainage of water from the aquifer, take the free surface as a moving boundary in a simulated region, and estimate the groundwater stage in the saturated region of unconfined aquifer by using the Finite Element Method.
A linear system can be obtained by solving the governing equation using the Finite Element Method. We use iteration method and take head as groundwater stage until the absolute value of the difference is under the allowed value. This study makes sum of the drainage in this mode and drawdown cone equal to the total pumping rate by adjusting the effective porosity after making the absolute value of the difference between the stage of the observation well and the corresponding node under the allowed value EA by adjusting the drainage in this mathematical model. By comparing with the values of effective porosity obtained from normal logarithm curves and semilog curves analysis method, the result is in a same order, which confirms the reliability and feasibility of the method propose in this paper.
Subjects
有限元素法
移動邊界
孔隙壓縮效應
Unconfined aquifers
Finite element Method
Moving boundary
Type
thesis
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