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1. A Non-Local Richards Equation to Model Unsaturated Flow in Highly Heterogeneous Media under Nonequilibrium Pressure Conditions

Author:
Neuweiler, Insa; Erdal, Daniel; Dentz, Marco
Source:
Vadose zone journal 2012 v.11 no.3
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; equations; mass transfer; mathematical models; prediction; seeds; vadose zone; water content;     Show all 8 Subjects
Abstract:
... We study the impact of mass transfer between high and low conductivity zones on flow in unsaturated media. A dual continuum approach that assumes capillary-dominated flow in the slow continuum gives a system of coupled flow equations for the water saturations in the mobile and in the slow domain, whose coupling term is directly related to the evolution of the averaged water content in the slow dom ...
DOI:
10.2136/vzj2011.0132

2. Dipole-Generated Unsaturated Flow in Gardner Soils

Author:
Kacimov, Anvar
Source:
Vadose zone journal 2007 v.6 no.1 pp. 168-174
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; mathematical models; soil water content; equations; soil heterogeneity; soil morphology; spatial variation;     Show all 7 Subjects
Abstract:
... The Bystrov explicit analytical solution for viscous, low-Reynolds number flow in layers of variable thickness is interpreted as infiltration in a Gardner homogeneous soil obstructed by a subterranean cavity, stone, or other obstacle. Mathematically, the two-dimensional advection–dispersion equation for the Kirchhoff potential is solved by combination of a term responsible for incident unidirectio ...
DOI:
10.2136/vzj2005.0141

3. Upscaling Schemes and Relationships for the Gardner and van Genuchten Hydraulic Functions for Heterogeneous Soils

Author:
Zhu, J.; Young, M.H.; Van Genuchten, M.T.
Source:
Vadose zone journal 2007 v.6 no.1 pp. 186
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; desert soils; soil heterogeneity; soil hydraulic properties; mathematical models; equations; soil water movement; soil water content; surface layers;     Show all 9 Subjects
Abstract:
... Upscaled soil hydraulic properties are needed for many large-scale hydrologic applications such as regional and global climate studies and investigations of land-atmosphere interactions. Many larger scale subsurface flow and contaminant transport studies also require upscaled hydraulic property estimates. The objectives of this study were to develop a methodology for upscaling hydraulic property f ...
Handle:
10113/3498
DOI:
10.2136/vzj2006.0041

4. Comments on "A Set of Analytical Benchmarks to Test Numerical Models of Flow and Transport in Soils"

Author:
Groenendijk, P.; Kroes, J.G.; Dam, J.C. van
Source:
Vadose zone journal 2006 v.5 no.1 pp. 126-127
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; vadose zone; soil water movement; mathematical models; hydrologic models; equations;     Show all 6 Subjects
DOI:
10.2136/vzj2005.0077L

5. A set of analytical benchmarks to test numerical models of flow and transport in soils

Author:
Vanderborght, J.; Kasteel, R.; Herbst, M.; Javaux, M.; Thiery, D.; Vanclooster, M.; Mouvet, C.; Vereecken, H.
Source:
Vadose zone journal 2005 v.4 no.1
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; vadose zone; soil water movement; mathematical models; hydrologic models; equations;     Show all 6 Subjects
Abstract:
... Accurate model predictions of water flow and solute transport in unsaturated soils require a correct representation of relevant mechanisms in a mathematical model, as well as correct solutions of the mathematical equations. Because of the complexity of boundary conditions and the nonlinearity of the processes considered, general solutions of the mathematical equations rely on numerical approximati ...

6. Darcy's Law and unsaturated flow

Author:
Narasimhan, T.N.
Source:
Vadose zone journal 2004 v.3 no.4
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; unsaturated conditions; equations; mathematical models; hydraulic conductivity;     Show all 5 Subjects

7. Application of a Darcian approach to estimate liquid flux in a deep vadose zone

Author:
Hubbell, J.M.; Nicholl, M.J.; Sisson, J.B.; McElroy, D.L.
Source:
Vadose zone journal 2004 v.3 no.2
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; mathematical models; waste disposal; equations; tensiometers; basalt; vadose zone; soil water movement; Idaho;     Show all 9 Subjects
Abstract:
... Approaches for estimating liquid flux in the shallow (0-2 m) vadose zone are hindered by the high degree of spatial and temporal variability present near the land surface. It is hypothesized that high-frequency variations in flux will be damped with depth. This study was conducted to estimate deep liquid flux using the Darcian approach at a waste disposal site in south-central Idaho that is underl ...

8. Correspondence and upscaling of hydraulic functions for steady-state flow in heterogeneous soils

Author:
Zhu, J.; Mohanty, B.P.; Warrick, A.W.; Van Genuchten, M.T.
Source:
Vadose zone journal 2004 v.3 no.2
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; mathematical models; unsaturated hydraulic conductivity; equations; soil water movement;     Show all 5 Subjects
Abstract:
... Soil hydraulic parameters at relatively large scales (e.g., remote sensing footprints) are important for land-atmosphere interaction and general circulation models as well as other applications. Within this context, we investigated two major issues involving soil hydraulic properties: (i) hydraulic parameter correspondence among some of the more commonly used soil hydraulic conductivity functions ...

9. Evaluation of the conceptual flow model for a deep vadose zone system using advanced tensiometers

Author:
McElroy, D.L.; Hubbell, J.M.
Source:
Vadose zone journal 2004 v.3 no.1
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; mathematical models; waste disposal; radionuclides; hazardous waste; equations; tensiometers; basalt; vadose zone; soil water movement; Idaho;     Show all 11 Subjects
Abstract:
... Conceptual flow models provide a framework for predictive modeling of contaminant transport. This study tests the assumptions of steady-state flow and a unit hydraulic gradient in a 177-m-thick vadose zone beneath a mixed waste site, using a network of advanced tensiometers. The conceptual flow model at the waste site, located on the Idaho National Engineering Laboratory (INEEL), describes moistur ...

10. Quantifying the effects of small-scale heterogeneities on flow and transport in undisturbed cores from the Hanford Formation

Author:
Pace, M.N.; Mayes, M.A.; Jardine, P.M.; Mehlhorn, T.L.; Zachara, J.M.; Bjornstad, B.N.
Source:
Vadose zone journal 2003 v.2 no.4
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; sediments; mathematical models; soil pollution; hazardous waste; unsaturated conditions; equations; pollutants; diffusion; preferential flow; vadose zone;     Show all 11 Subjects
Abstract:
... Accelerated migration of contaminants in the vadose zone has been observed beneath tank farms at the U.S. Department of Energy's Hanford Reservation, Richland, WA. This paper focuses on quantifying hydrologic processes that control the fate and transport of contaminants in the unsaturated sediments beneath the Hanford tank farms. The experimental approach involved the use of field relevant, long-t ...

11. Stochastic analysis of transient flow in heterogeneous, variably saturated porous media: the van Genuchten-Mualem constitutive model

Author:
Lu, Z.; Zhang, D.
Source:
Vadose zone journal 2002 v.1 no.1
ISSN:
1539-1663
Subject:
unsaturated flow,   etc   ; saturated flow; porous media; vadose zone; soil water movement; mathematical models; stochastic processes; equations; Monte Carlo method; temporal variation; spatial variation;     Show all 11 Subjects
Abstract:
... In this study, on the basis of the van Genuchten-Mualem constitutive relationship, we develop a general nonstationary stochastic model for transient, variably saturated flow in randomly heterogeneous media with the method of moment equations. We first derive partial differential equations governing the statistical moments of the flow quantities by perturbation expansions and then implement these e ...