Numerical simulation of transient water infiltration in heterogeneous soils combining central schemes and mixed finite elements

Abstract

AbstractWe present a new numerical scheme for the approximation of solutions of transient water infiltration problems in heterogeneous soils. The two‐phase (water and air) flow problem is governed by a pressure–velocity equation coupled to a saturation equation. The numerical scheme combines a non‐oscillatory, second‐order, conservative central finite differencing scheme for the saturation equation with mixed finite elements for the pressure–velocity equation. An operator splitting technique allows for the use of distinct time steps for the solution of the equations of the governing system. One and two‐dimensional numerical experiments show that the proposed scheme is able to capture accurately and efficiently sharp fronts in two‐phase water–air problem. The simulations were carried out taking into account the effects of gravity and capillary diffusion forces. Copyright © 2006 John Wiley & Sons, Ltd.