Solutions for Non‐Darcian Flow to an Extended Well in Fractured Rock |
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| Authors: | Zhang Wen Guanhua Huang Hongbin Zhan |
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| Institution: | 1. School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430074, China;2. wenzhangcau@gmail.com;3. Department of Irrigation and Drainage, College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing 100083, China.;4. Department of Geology and Geophysics, Texas A & M University, College Station, TX 77843‐3115;5. zhan@geo.tamu.edu;6. Faculty of Engineering, China University of Geosciences, Wuhan, Hubei 430 074, China. |
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| Abstract: | We have investigated non‐Darcian flow to a vertical fracture represented as an extended well using a linearization procedure and a finite difference method in this study. Approximate analytical solutions have been obtained with and without the consideration of fracture storage based on the linearization procedure. A numerical solution for such a non‐Darcian flow case has also been obtained with a finite difference method. We have compared the numerical solution with the approximate analytical solutions obtained by the linearization method and the Boltzmann transform. The results indicate that the linearized solution agrees generally well with the numerical solution at late times, and underestimates the dimensionless drawdown at early times, no matter if the fracture storage is considered or not. When the fracture storage is excluded, the Boltzmann transform solution overestimates the dimensionless drawdown during the entire pumping period. The dimensionless drawdowns in the fracture with fracture storage for different values of dimensionless non‐Darcian hydraulic conductivity β approach the same asymptotic value at early times. A larger β value results in a smaller dimensionless drawdown in both the fracture and the aquifer when the fracture storage is included. The dimensionless drawdown is approximately proportional to the square root of the dimensionless time at late times. |
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