A numerical model for transient-hysteretic flow and solute transport in unsaturated porous media
Document Type
Article
Publication Date
4-1-1998
Abstract
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. The unsaturated flow and transport model was applied to a variety of rigorous problems and was found to produce accurate, mass- conserving solutions when compared to analytical solutions and published numerical results.
Publication Title
Journal of Contaminant Hydrology
Recommended Citation
Mitchell, R.,
&
Mayer, A.
(1998).
A numerical model for transient-hysteretic flow and solute transport in unsaturated porous media.
Journal of Contaminant Hydrology,
30(3-4), 243-264.
http://doi.org/10.1016/S0169-7722(97)00042-9
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/7451