VS2DT - flow and solute transport in variably-saturated, single-phase flow in porous media
VS2DT Categories: flow models - unsaturated zone, solute transport models - unsaturated zone
VS2DT is a USGS program for flow and solute transport in variably-saturated,
single-phase flow in porous media. A finite-difference approximation is used in VS2DT to solve the advection-dispersion equation. Simulated regions include one-dimensional columns, two-dimensional vertical cross
sections, and axially-symmetric, three-dimensional cylinders. The VS2DT Program options include backward or centered approximations for both space and time derivatives, first-order decay, equilibrium adsorption
(Freundlich or Langmuir) isotherms, and ion exchange. Nonlinear storage terms are linearized by an implicit Newton-Raphson method. Relative hydraulic conductivity in VS2DT is evaluated at cell boundaries using full
upstream weighting, arithmetic mean or geometric mean. Saturated hydraulic conductivities in VS2DT are evaluated at cell boundaries using distance-weighted harmonic means.
A graphical user interface for VS2DT is now available in the WHI UnSat Suite. The VS2DT model is also included.