General Validity of Conductivity Means in Unsaturated Flow Models
Publication: Journal of Hydrologic Engineering
Volume 11, Issue 6
Abstract
A simple three-point grid test shows that some common and mathematically convenient intergrid hydraulic conductivity means violate the min–max principle for elliptic boundary value problems (steady-state flow). In some cases in models of Richard's equation for three types of homogenous rock matrix and fracture in Yucca Mountain tuff, these violations lead to nonphysical oscillations, eliminating these means as generally valid approaches in such models. These models are used to show that Darcian means and the upstream means have similar RMS errors in water content and flow in convergence to the fine-grid solution. But in the presence of vertical space step discretization error, the Darcian means produce sharper wetting fronts.
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Information & Authors
Information
Published In
Journal of Hydrologic Engineering
Volume 11 • Issue 6 • November 2006
Pages: 526 - 538
Copyright
© 2006 ASCE.
History
Received: Mar 20, 2002
Accepted: Feb 28, 2006
Published online: Nov 1, 2006
Published in print: Nov 2006
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