Titre :
|
A numerical model for transient-hysteretic flow and solute transport in unsaturated porous media
|
Auteurs :
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R. Mitchell ;
A. Mayer
|
Type de document :
|
article/chapitre/communication
|
Année de publication :
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1998
|
Format :
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p. 243-264
|
Langues:
|
= Anglais
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Catégories :
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HYDROLOGIE ET HYDRAULIQUE
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Mots-clés:
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SOLUTE
;
TRANSPORT DE CONTAMINANT
;
ECOULEMENT TRANSITOIRE
;
MILIEU POREUX
;
MILIEU NON SATURE
;
MODELE NUMERIQUE
|
Résumé :
|
A two-dimensional flow and transport model was developed for simulating transient water flow and nonreactive solute transport in heterogeneous, unsaturated porous media containing air and water. The model is composed of a unique combination of robust and accurate numerical algorithms for solving the Richards', Darcy flux, and advection-dispersion equations. The mixed form of Richards' equation is solved using a finite-element formulation and a modified Picard iteration scheme. Mass lumping is employed to improve solution convergence and stability behavior. The flow algorithm accounts for hysteresis in the pressure head-water content relationship. Darcy fluxes are approximated with a Galerkin and Petrov-Galerkin finite-element method developed for random heterogeneous porous media. The transport equation is solved using an Eulerian-Lagrangian method. A multi-step, fourth-order Runge-Kutta, reverse particle tracking technique and a quadratic-linear interpolation scheme are shown to be superior for determining the advective concentration. A Galerkin finite-element method is used for approximating the dispersive flux.
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Source :
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Journal of contaminant hydrology, vol.50
|