A Study of the Effect of Microstructure on the Anisotropy of
Hydraulic Conductivity Using the Lattice-Boltzmann Method.
(4339)
Authors:
D. Rector - Pacific Northwest National Laboratory M. Stewart* - Pacific Northwest National Laboratory A. Ward - Pacific Northwest National Laboratory
Abstract:
It has been observed that in unsaturated soils, anisotropy in hydraulic conductivity varies with the degree of saturation, making it difficult to predict even in relatively homogenous soils. We hypothesize that this effect arises from anisotropy at the scale of individual pores which is associated with the alignment of aspherical particles and can be quantified through a pore connectivity tensor. Our
objective was to develop a theoretical framework for the prediction of the connectivity and permeability tensors from soil particle shape and packing structure. Random packing geometries of particles with various aspect ratios were generated using a numerical packing algorithm. The lattice-Boltzmann
method was used to simulate saturated flow through these packs. The effect of particle shape and degree of alignment on the permeability tensor was characterized for each pack. Results show that the degree of anisotropy in permeability depends not only upon particle shape and alignment, but also upon the three dimensional structure of the pack. Trends indicate that more oblate particles and higher degrees of particle alignment result in greater anisotropy. This approach is currently being extended to unsaturated conditions.
Speaker Information: Mark Stewart, Pacific Northwest National Laboratory, 902 Battelle BoulevardP.O.
Box 999MSIN: K7-15, Richland, WA 99352; Phone: 509-375-2179; E-mail: [email protected]
Session Information: Wednesday, November 3, 2004, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 2809)
Keywords: permeability; lattice-Boltzmann; hydraulic conductivity; anisotropy
