VS2D/T

Category  Contaminant transport (2D FD) 
Platform  DOS 
Status  Commercial 
Description  VS2D/T is a twodimensional finite difference simulator for crosssectional or cylindrical variably saturated flow in porous media. The model allows consideration of nonlinear storage, conductance, and sink terms and boundary conditions. Processes included are infiltration, evaporation and plant root uptake. The program also handles seepage faces. It is a solute transport module to be used with VS2D. It is based on a finite difference approximation of the advectiondispersion equation for a single species. Program options include firstorder decay, equilibrium adsorption described by Freundlich or Langmuir isotherms, and ionexchange. Nonlinear storage terms are linearized by an implicit NewtonRaphson method. Nonlinear conductance terms, boundary conditions, and sink terms are linearized implicitly. Relative hydraulic conductivity is evaluated at cell boundaries by using full upstream weighting, the arithmetic mean, or the geometric mean of values of adjacent cells. Saturated hydraulic conductivities are evaluated at cell boundaries by using distance weighted harmonic means. The linearized matrix equations are solved using the strongly implicit method. Nonlinear conductance and storage coefficients are represented by closedform algebraic equations or interpolated from tables. Nonlinear boundary conditions treated by the code include infiltration, evaporation, and seepage faces. Extraction by plant roots is included as a nonlinear sink term. Initial conditions may be input as moisture content or pressure head by blocks defined by row and column, or in a formatted file by cell. An equilibrium profile may be specified above a user defined free water surface. Infiltration may be simulated by specified flux nodes, specified pressure nodes, or a ponding function where the user specifies rainfall rate and ponding height. Evaporation is simulated by a user defined potential evapotranspiration, pressure potential of the atmosphere, and surface resistance. Evapotranspiration is simulated through the use of user defined potential evapotranspiration, minimum root pressure, depth of rooting, and root activity at the bottom of the root zone and land surface. Seepage faces may also be simulated. 
Cost  US Dollars 250 
Data formats supported  None stated 
Supplier in United States of America  International Ground Water Modeling Center 
Supplier in United States of America  Scientific Software Group 
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