<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Flow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighbouring nodes or cells of the numerical grid. The present paper discusses application of the computer simulation code VS2DI to three test problems concerning infiltration into an initially dry medium, using various methods for inter-cell conductivity calculation (arithmetic mean, geometric mean and upstream weighting). It is shown that the influence of the averaging method can be very large for coarse grid, but that it diminishes as cell size decreases. Overall, the arithmetic average produced the most reliable results for coarse grids. Moreover, the difference between results obtained with various methods is a convenient indicator of the adequacy of grid refinement.</p></abstract>

Flow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighbouring nodes or cells of the numerical grid. The present paper discusses application of the computer simulation code VS2DI to three test problems concerning infiltration into an initially dry medium, using various methods for inter-cell conductivity calculation (arithmetic mean, geometric mean and upstream weighting). It is shown that the influence of the averaging method can be very large for coarse grid, but that it diminishes as cell size decreases. Overall, the arithmetic average produced the most reliable results for coarse grids. Moreover, the difference between results obtained with various methods is a convenient indicator of the adequacy of grid refinement.

Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes

Gdańsk University of Technology, Faculty of Civil and Environmental Engineering, Narutowicza 11/12, 80-233 Gdańsk, Poland

Geologos

This chapter is distributed under the terms of the Creative Commons Attribution 4.0 Public License.

Flow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water...

Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes

Published Online: Oct 20, 2015

Page range: 161 - 167

Received: Feb 19, 2015

Accepted: Jun 19, 2015

DOI: https://doi.org/10.1515/logos-2015-0015

Keywords
numerical modelling, Richards equation, hydraulic conductivity

© 2015 Adam Szymkiewicz et al., published by De Gruyter Open

This chapter is distributed under the terms of the Creative Commons Attribution 4.0 Public License.

Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes

Published Online: Oct 20, 2015

Page range: 161 - 167

Received: Feb 19, 2015

Accepted: Jun 19, 2015

DOI: https://doi.org/10.1515/logos-2015-0015

Keywordsnumerical modelling, Richards equation, hydraulic conductivity

© 2015 Adam Szymkiewicz et al., published by De Gruyter Open

This chapter is distributed under the terms of the Creative Commons Attribution 4.0 Public License.

Keywords
numerical modelling, Richards equation, hydraulic conductivity