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