scholarly journals A new model for soil hydraulic properties based on a stochastic conceptualization of porous media

2003 ◽  
Vol 39 (7) ◽  
Author(s):  
T. P. Chan ◽  
R. S. Govindaraju
Keyword(s):  
Porous Media ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
New Model ◽  
Soil Hydraulic

Pore-morphology-based simulations of drainage and wetting processes in porous media

2011 ◽  
Vol 42 (2-3) ◽  
pp. 128-149 ◽  
Author(s):  
T. P. Chan ◽  
Rao S. Govindaraju
Keyword(s):  
Porous Media ◽  
Hydraulic Properties ◽  
Pore Space ◽  
Water Pressure ◽  
Theoretical Models ◽  
Hysteretic Behavior ◽  
Water Retention Curve ◽  
Pore Morphology ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic

Soil hydraulic properties relating saturation, water pressure, and hydraulic conductivity are known to exhibit hysteresis. In this paper, we focus on the determination of the water retention curve for a porous medium through a novel pore-scale simulation technique that is based on mathematical morphology. We develop an algorithm that allows for the representation of three-dimensional randomly packed porous media of any geometry (i.e. not restricted to idealized geometries such as spherical or ellipsoidal particles/pore space) so that the connectivity-, tortuosity-, and hysteresis-causing mechanisms are represented in both drainage and wetting processes, and their role in determining macroscopic fluid behavior is made explicit. Using this method, we present simulation results that demonstrate hysteretic behavior of wetting and non-wetting phases during both drainage and wetting cycles. A new method for computing interfacial surface areas is developed. The pore-morphology-based method is critically evaluated for accuracy, sample size effects, and resolution effects. It is found that the method computes interfacial areas more accurately than existing methods and allows for (i) examination of relationships between water pressure, saturation and interfacial area for hysteretic soils, and (ii) comparisons with previously developed theoretical models of soil hydraulic properties. The pore-morphology-based method shows promise for applications in vadose zone hydrology.

scholarly journals Sensitivity analysis of unsaturated infiltration flow using head based finite element solution of Richards' equation

MATEMATIKA ◽  
2017 ◽  
Vol 33 (2) ◽  
pp. 131 ◽  
Author(s):  
Mohammad Sayful Islam
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Porous Media ◽  
Hydraulic Properties ◽  
Preferential Flow ◽  
Finite Element Solution ◽  
Richards Equation ◽  
Element Solution ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic

Sensitivity analysis is one of the tools available for analyzing the effects of soil parameter on the variably unsaturated flows in porous media, that may easily be implemented into existing conventional Galerkin finite element solution of Richards’ equation based computational fluid dynamics codes. The sensitivity of the model is evaluated on the basis vertical infiltration problem with time dependent boundary condition, sharp gradient in the infiltration front, and discontinuous derivatives in the soil hydraulic properties. Simulation results demonstrate the complicated nature of unsaturated porous media during redistribution water flow.  The sample case presented highlight different aspects of the performance of the algorithm and the different factors that can affect their convergence and efficiency, including temporal discretization, convergence error norm, conductivity and moisture content characteristics, boundary conditions, and the extent of fully unsaturated zones in the soil. From the preliminary assessment performed herein, consideration of the number of degrees of freedom used when performing a sensitivity analysis is shown to demand enormous concern, if predicted sensitivities are to have significant physical interpretations. The proposed model is capable of simulating preferential flow situations using parameters which can be related to soil hydraulic properties.

A modified upward infiltration method for characterizing soil hydraulic properties

2002 ◽  
Vol 66 (1) ◽  
pp. 57 ◽  
Author(s):  
M. H. Young ◽  
A. Karagunduz ◽  
J. Šimůnek ◽  
K. D. Pennell
Keyword(s):  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
Infiltration Method

scholarly journals Pinhole Multistep Centrifuge Outflow Method for Estimating Unsaturated Hydraulic Properties with Small Volume Soil Samples

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1169
Author(s):  
Long Thanh Bui ◽  
Yasushi Mori
Keyword(s):  
Hydraulic Properties ◽  
Volcanic Ash ◽  
Small Volume ◽  
Clayey Soil ◽  
Soil Hydraulic Properties ◽  
Retention Curve ◽  
Volcanic Ash Soil ◽  
Equilibrium Data ◽  
Soil Hydraulic ◽  
Water Holding

If soil hydraulic conductivity or water holding capacity could be measured with a small volume of samples, it would benefit international fields where researchers can only carry a limited amount of soils out of particular regions. We performed a pinhole multistep centrifuge outflow method on three types of soil, which included granite decomposed soil (Masa soil), volcanic ash soil (Andisol soil), and alluvial clayey soil (paddy soil). The experiment was conducted using 2 mL and 15 mL centrifuge tubes in which pinholes were created on the top and bottom for air intrusion and outflow, respectively. Water content was measured at 5, 15, and 30 min after applying the centrifuge to examine the equilibrium time. The results showed that pinhole drainage worked well for outflow, and 15 or 30 min was sufficient to obtain data for each step. Compared with equilibrium data, the retention curve was successfully optimized. Although the curve shape was similar, unsaturated hydraulic conductivities deviated largely, which implied that Ks caused convergence issues. When Ks was set as a measured constant, the unsaturated hydraulic properties converged well and gave excellent results. This method can provide soil hydraulic properties of regions where soil sampling is limited and lacks soil data.

scholarly journals The effects of long-term fertilizations on soil hydraulic properties vary with scales

2021 ◽  
Vol 593 ◽  
pp. 125890
Author(s):  
Xiaoxian Zhang ◽  
Andrew L. Neal ◽  
John W. Crawford ◽  
Aurelie Bacq-Labreuil ◽  
Elsy Akkari ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic
Sign in / Sign up

Export Citation Format

Share Document