Numerical solution to non-Darcian effect on transient confined-unconfined flow
In order to investigate the mechanism of transient confined-unconfined flow towards a fully penetrated pumping well in a confined aquifer,this study develops a numerical model considered non-Darcian effect.The Izbash's equation is used to describe nonlinear relationship between the specific discharge and the hydraulic gradient,and the numerical solution is derived by finite difference method.The acceptability of the proposed model is verified by the comparison with the Darcian seepage model.The results showed that the non-Darcian index,quasi-hydraulic conductivity and specific storage have negative effects on the development of the unconfined region and the drawdown of the aquifer,resulting from that the greater degree of turbulence flow accelerates the recharge to the pumping well.Through sensitivity analysis,it is noted that the drawdown is sensitive to the non-Darcian index,quasi-hydraulic conductivity,but not sensitive to the specific yield and specific storage.
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