ISSN:
1745-6584
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Geosciences
Notes:
We examine flow in an unconfined aquifer near a recirculation well, which consists of a source and a sink of equal discharge, with emphasis on understanding the behavior of the free surface. The well is vertical with a pump located between an inlet above and an outlet below to induce recirculation of ground water and thus enhance mixing. The boundary element method is used to model the flow with the free-surface boundary condition. Numerical simulations show that for this arrangement there is a critical pumping rate beyond which the free surface becomes unstable and is drawn down to the well. The value of this critical rate as well as the maximum drawdown of the phreatic surface were determined for a range of well-screen (inlet and outlet) separations. In addition to the numerical model, we developed an analytical approximation that yielded an estimate of the critical pumping rate. The analytical estimate is shown to be in reasonably good agreement with the numerical results. We also examined the effect of approximating the free-surface boundary by a horizontal confining layer. The radius of influence of a single well source-sink pair was only slightly affected by making this approximation, as long as the pumping rate remained below the critical value.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1745-6584.1993.tb00850.x
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