engleski

Effective Macrodiffusion in Solute Transport Through Heterogeneous Porous Media

Homogenization method is used to analyze the global behavior of passive solute transport through highly heterogeneous porous media. The flow is governed by a coupled system of an elliptic equation and a linear convection-diffusion concentration equation with a diffusion term small with respect to the convection, i.e. with a relatively high Peclet number. We use asymptotic expansions techniques in order to define a macroscale transport model. Numerical computations to obtain the effective hydraulic conductivity and the macrodiffusivity tensor are presented, using finite volume methods. Numerical experiments based on typical situations encountered in the simulations of solute transport have been performed comparing the transport in the heterogeneous medium to the transport in the corresponding effective medium. The results of the simulations are compared in terms of spatial moments, $L^2$ errors and concentration contours. From all those points of view the results obtained from the simulations using the effective model obtained by the homogenization method show good agreement with the heterogeneous simulations.

dispersion; heterogeneous porous media; homogenization; solute transport

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