Two-scale modeling of unsaturated water flow in a double-porosity medium under axisymmetric conditions

Abstract

International audienceIn this paper the development and experimental validation of a numerical model of two-dimensional unsaturated flow in a double-porosity medium is presented. The model is based on the coupled formulation for flow in macro- and micropores obtained by homogenization. It was applied to simulate the axisymmetrical tension disk infiltration experiments that were carried out in a double-porosity medium. The physical model was a three-dimensional periodic structure, composed of porous spheres made of sintered clay and embedded in Hostun fine sand HN38. The hydraulic parameters of both porous materials were determined by inverse analysis of independent infiltration experiments performed on sand and sintered clay. The effective parameters of the double-porosity medium were calculated from the solution of the local boundary value problem, obtained from the homogenization procedure. The cumulative infiltration curve and the global dimensions of the humidified zone obtained from the numerical solution are in good agreement with the observations. Moreover, numerical simulations showed the existence of a narrow zone of local nonequilibrium that moves with the infiltration front. Upstream of this zone, the infiltration bulb is in the local equilibrium conditions

A review of model applications for structured soils: a) Water flow and tracer transport

“…DPOR-2D (Szymkiewicz et al, 2008) is the 2D equivalent of DPOR-1D. 2DCHEM (Nieber and Misra, 1995) is a 2D DPM for application in drained soils.…”

“…A similar procedure for parameterizing a DPM resulted in a satisfactory simulation of water drainage from a repacked soil column with cylindrical PF region . The 2D counterpart of DPOR-1D, named DPOR-2D, was successfully tested using data obtained from an axi-symmetrical experimental infiltration setup with a similar mixture of sand and sintered clay spheres (Szymkiewicz et al, 2008).…”

Two‐scale modeling of solute dispersion in unsaturated double‐porosity media: Homogenization and experimental validation

“…The next order problem (24)-(25)- (27) developed in [24] allowed to obtain the solution for h (1) 1 in the form of…”

“…This model is associated with the unsaturated water flow model, which was previously developed by applying the homogenization method [24]. The solute transport model was validated through fully controlled NaCl dispersion experiments on a DP physical model of known microstructure, the same which was previously used for the validation of the DP unsaturated water flow model [25][26][27]. The paper is structured as follows.…”

Simulation of micro-scale porous flow using Smoothed Particle Hydrodynamics

“…This provides the perfect motivation for moving towards a completely coupled, dual-scale modelling approach. Dual-scale models seek to couple the volume-averaged scale interdependently with the scale of the porous microstructure by imposing suitably defined boundary conditions on the microscopic problem [19,4]. This strategy avoids the need to define macroscopic quantities, such as relative permeability, that are challenging to define and often difficult to determine experimentally.…”