Simulation of Fluid Flow and Permeability in Cohesionless Soils.
Simulation of Fluid Flow and Permeability in
Cohesionless Soils.
(1323 K)
Martys, N. S.; Masad, E.; Muhunthan, B.
Water Resources Research, Vol. 36, No. 4, 851-864,
April 2000.
Keywords:
permeability; fluid flow; simulation
Abstract:
This paper reports on a new laboratory methodology for
the determination of the structure of pores, a method
for the analysis of the data to obtain the statistics of
the pore structure distribution, simulation of porous
media with statistics consistent with those in the
specimens, numerical simulation of fluid flow in images
of porous media, and the determination of permeabilities
from the numerical experiments and comparison with the
results of laboratory experiments. The computed flow
fields show that flow in porous media is restricted to
preferential paths depending on the size and
connectivity of pores. Whole areas of the pore structure
are relatively isolated from the flow because of
bottlenecks. The distribution of the isolated regions
depends on the angularity of the grains and the porosity
of the medium. The more angular the grains are the
greater is the possibility for the presence of isolated
regions. For grains with the same angularity a decrease
in the porosity leads to concentration of flow along
preferential flow paths. The permeability tensor
coefficients are derived from the flow fields of the
two-dimensional images as well as the three-dimensional
computer-simulated images of soil microstructure. The
numerical values of permeability and permeability
anisotropy ratio compare well with laboratory
experimental data.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899