| Abstract: | This report documents FORTRAN computer code for solving problems involving variably saturated single-phase flow in porous media. The flow equation is written with total hydraulic potential as the dependent variable, which allows straightforward treatment of both saturated and unsaturated conditions. The spatial derivatives in the flow equation are approximated by central differences, and time derivatives are approximated either by a fully implicit backward or by a centered-difference scheme. Nonlinear conductance and storage terms may be linearized using either an explicit method or an implicit Newton-Raphson method. Relative hydraulic conductivity is evaluated at cell boundaries by using either full upstream weighting, the arithmetic mean, or the geometric mean of values from adjacent cells. Nonlinear boundary conditions treated by the code include infiltration, evaporation, and seepage faces. Extraction by plant roots that is caused by atmospheric demand is included as a nonlinear sink term. These nonlinear boundary and sink terms are linearized implicitly. The code has been verified for several one-dimensional linear problems for which analytical solutions exist and against two nonlinear problems that have been simulated with other numerical models. A complete listing of data-entry requirements and data entry and results for three example problems are provided. (USGS) |
| Genre: | USGS Numbered Series |
| ProdID: | 28260 |
| Citation Author: | Lappala, E. G.; Healy, R. W.; Weeks, E. P. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | ix, 184 p. :ill. ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 83-4099 |
| Citation Search Results Text: | Documentation of computer program VS2D to solve the equations of fluid flow in variably saturated porous media; 1987; WRI; 83-4099; Lappala, E. G.; Healy, R. W.; Weeks, E. P. |
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| Citation Year: | 1987 |
| Type: | citation/reference |
| Text: | Documentation of computer program VS2D to solve the equations of fluid flow in variably saturated porous media; 1987; WRI; 83-4099; Lappala, E. G.; Healy, R. W.; Weeks, E. P. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wri/1983/4099/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wri/1983/4099/report.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
