HR: 15:25h
AN: H43J-08    [Abstracts]
TI: Flow and anomalous transport through a three-dimensional pore
AU: * Cardenas, M B
EM: cardenas@mail.utexas.edu
AF: Department of Geological Sciences, The University of Texas at Austin, 1 University Station C1100, Austin, TX 78712, United States
AB: Flow and transport through porous media is a ubiquitous and fundamental geologic process. Three-dimensional Navier-Stokes flow and transport simulations are conducted for a single pore throat between cubic-packed grains 1-2 mm in diameter to advance our fundamental understanding of porous media processes. The grains are considered either spherical or ellipsoidal, and flow between the grains at different Reynolds number is oriented along or across the long axis of the grains. Discharge varied linearly with imposed pressure gradients directly verifying Darcy's Law at the single-pore scale. Vortices are present near the pore throats with narrower and deeper pore throats displaying a series of vortices. The vortices drive non-Fickian tailing of solutes resulting in power-law residence time distributions. Different tailing behavior is observed since the vortices are sensitive to grain shape and flow orientation. Over-all, solute transport through single pores cannot be described by a one-dimensional advection-dispersion equation where "dispersive" transport follows Fick's Law. This suggests that the transport process is below a continuum scale and that anomalous transport characterizes the single-pore scale. At this scale, Darcy's Law holds but Fick's Law does not.
DE: 1805 Computational hydrology
DE: 1828 Groundwater hydraulics
DE: 1847 Modeling
DE: 1858 Rocks: chemical properties
DE: 1859 Rocks: physical properties
SC: Hydrology [H]
MN: 2007 Fall Meeting