Purpose: To provide a multi-scale theoretical

and computational model of variably saturated granular/porous media that will improve our ability to perform engineering-scale analyses.

Product/Results:Theoretical and computational

modeling frameworks for air/water/particle systems.

New constitutive relations for macroscopic models of porous media.

Payoff:Understanding how the microscopic

properties of variably saturated media relate to the engineering scale properties will lead to improved ability to detect subsurface features, to build reliable structures, and to predict transport in soils.

Schedule & Cost

Total$738K

MILESTONES Prior FY08 FY09 FY10Years

Army ($K)

Other

Initial Plan/Prep

Particle-Scale Theory

Particle-Scale Simulator

Three-phase Theory

Three-phase Simulator

Multiscale Theory

Multiscale Simulator

Particle-Scale Distribution of Soil Moisture in Porous Materials

Status:Basic6.1

$738KTotal Army

Program

227 261 250

What is the Problem? – We don’t understand the macroscopic structural, hydraulic, thermal, electromagnetic, and chemical properties of variably saturated soils. These properties affect our ability to detect subsurface targets and features, build structures, and predict chemical species transport in soils.

What are the barriers to solving the problem? – Accurately measuring thermodynamic conjugate variables in physical experiments under dynamic conditions, as required for formulation of fundamentally sound constitutive relationships, is not possible. Quantities such as phase pressures, surface tension, fluid phase distribution, fluid phase kinetic and potential energies cannot be independently measured at the pore scale.  

Collaboration across ERDC, commercial firms and/or academia –

High Fidelity Vessel Effects Project (CHL), Level-set methods GEOTACS/IMTPS (GSL), Macroscale models DAAC (MSRC) 3D viz and data formatsKitware, Inc. (Albany) - 3D viz and sotware developmentY. Bazilevs (UC-San Diego), Multiscale numerical methodsG. Carey and C. Dawson (UT-Austin), Finite element analysisJ. Chrispell (Tulane), Immersed interface methodsD. DiCarlo and M. Prodanovic (UT-Austin), Pore-scale modelsS. Gasda and C. Miller (UNC-Chapel Hill), Macroscale modelsP. Imhoff (Delaware), Macroscale modelsL. Jenkins (Clemson), Numerical methodsC. Willson (LSU), Particle scale measurements

What is innovative about this work? The use of particle-scale continuum fluid mechanics simulations that explicitly model the separate phases and the fluid-water and fluid-solid interfaces. The coupling of those models to discrete element models of granular materials to facilitate multi-scale numerical modeling of these systems.

What is your publication plan? FY07 - Mini-symposium on near surface air/water flow at U.S.

National Congress on Computational Mechanics (July). FY08 - Computer Methods in Applied Mechanics and

Engineering (in review). FY09 - Journal of Computational Physics (In preparation),

Advances in Water Resources (in preparation).

Particle-Scale Distribution of Soil Moisture in Porous Materials

How will you overcome these barriers? – Apply state-of-the-art computational methods to rigorous continuum thermo-mechanical models of the interaction of air and water phases in granular materials; collaborate with experimentalists and numerical analysis specialists from academia.

What are the results of this research and what is its value? – A multiscale theoretical and computational modeling capability for variably saturated granular materials. The ability to calculate macroscopic properties from particle-scale measurements and/or use simulations to supplement experimental methods in complex three-dimensional settings where direct observation of all physical quantities is not possible; a computational multiscale framework that can be used to carry out fundamentally sound engineering analyses.