Discrete Network Modeling for Field-Scale Flow and Transport Through Porous Media
Abstract
Natural soil is a discrete, heterogeneous porous material with many sizes of physical structure. These multi-scale discrete media resist description by differential equations with macroscopic parameters. Constitutive parameters may display an apparent scale dependence or the governing equations may exhibit non-physical behavior. To address these issues, a discrete-medium modeling philosophy is adopted that relies less on complex constitutive theory and more on computational resolution. Specifically, a stochastic, high-resolution, discrete network model is developed and explored for simulating macroscopic flow and conservative transport through macroscopic porous media Networks can be created to honor macroscopic porosity, effective conductivity, and apparent dispersivity estimates or to honor statistical distributions of small scale conductivites. Flow through a discrete network compares well with analytical solutions for macroscopic, Darcian fluid flow. Transport through a discrete network differs fundamentally from advection-dispersion theory. However, network-predicted concentration profiles and breakthrough curves are consistent with historical observations of nearly-Gaussian concentration distributions. Dispersion in the network is a natural consequence of its discrete structure. For immiscible flow, network models offer the potential to simulate capillary barriers and macroporous breakthrough phenomena.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1997
- Accession Number
- ADA332997
Entities
People
- John F. Peters
- Stacy E. Howington
- Tissa H. Illangasekare