1. General Model Information

Name: Variably SAturated Flow and Transport in 2 dimensions

Acronym: VSAFT


Main medium: terrestrial
Main subject: hydrology, biogeochemistry
Organization level: Ecosystem
Type of model: partial differential equations (finite elements,2D)
Main application:
Keywords: soil, water, unsaturated flow, solute transport, richards equatin, convection-dispersion equation

Contact:

Yeh, T-C.J.

University of Arizona
Tucson, AZ 85721

phone:
fax:
email:

Author(s):

Yeh,T-C. J.

Abstract:

VSAFT2 is a program for simulating two-dimensional steady or transient, variably saturated flow and convective-dipersive transport of a conservative solute, using a finite element method with the Newton-Raphson or Picard iteration scheme. For the linear equation solution a preconditioned conjugate gradient method is used. Solute transport is handled by an upstream weighting scheme. The model uses rectangular and/or triangular finite elements and a banded matrix solver. The two-dimensional flow can be either in a horizontal or in a vertical plane. Furthermore, the model can handle radial symmetric simulations. The code contains a restart feature for simulation of changing boundary conditions. Evapotranspiration is simulated in VSAFT2 by a user specified root zone consisting of one or more plant species. Information on the root zone includes wilting pressure, maximum transpiration rate, root effectiveness function, and root zone geometric data. Evaporation\Infiltration is simulated through user defined maximum evaporation or infiltration rates, minimum soil surface pressure head, and soil surface geometric data.

Analytical fuctions must be used for relative hydraulic relationship and moisture characteristic curve fuctions. The user is given the choice of the van Genuchten model, eponential model, Gardner-Russo model, or a user specified fuction for which a subroutine must be written.


II. Technical Information

II.1 Executables:

Operating System(s): DOS, UNIX

II.2 Source-code:

Programming Language(s): FORTRAN

II.3 Manuals:



II.4 Data:



III. Mathematical Information


III.1 Mathematics


III.2 Quantities


III.2.1 Input

Initial and boundary conditions.

Analytical fuctions must be used for relative hydraulic relationship and moisture characteristic curve fuctions. The user is given the choice of the van Genuchten model, eponential model, Gardner-Russo model, or a user specified fuction for which a subroutine must be written.

III.2.2 Output


IV. References



V. Further information in the World-Wide-Web


VI. Additional remarks


Last review of this document by: Tue Sep 30 11:43:24 1997
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:52 CEST 2002

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