Abstract

PEDROZO, Hector A; ROSENBERGER, Mario R  and  SCHVEZOV, Carlos E. Comparison of Finite Difference Models Applied to Soil Infiltration. Rev. cienc. tecnol. [online]. 2015, n.23, pp.36-44. ISSN 1851-7587.

Infiltration, that is the process by which water enters a porous medium, is described by Richards’ equation. This equation and the associated constitutive equations are markedly nonlinear. In the present research work, Richards’ equation is solved by using different approximations in finite differences, and by analyzing the calculation speed and the result sensitivity for different time step values they are compared. Three different methods of calculation were used to solve it: the explicit method (ME), the simple implicit method (MIS) and the Crank-Nicolson method (MCN). In the present work, Dirichlet boundary conditions were taken. It was found that the three models converge to the same solution for the sensitivity analysis of the Δt variable and the Crank-Nicolson’s model has the lowest relative errors in the area of the wet front which, despite its complexity, requires reduced computation time.

Keywords : Numerical methods; Richards’ equation; Porous media; Implicit methods; Explicit methods.

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