Fractal Growth in Hydrodynamic Dispersion Through Random Porous Media.
Fractal Growth in Hydrodynamic Dispersion Through Random
Porous Media.
(4501 K)
Martys, N. S.
Physical Review E, Vol. 50, No. 1, 335-342, July 1994.
Keywords:
dispersions; tracers; dyes; fluid flow; diffusion;
scaling
Abstract:
Results from the numerical simulation of hydrodynamic
dispersion in model random porous media are presented.
The morphology of a spreading dye (or tracer), as a
function of Peclet number, is studied. In the limit of
infinite Peclet number, the dye pattern formed is
fractal with fractal dimension close to that observed in
diffusion-limited aggregation (DLA) in both two and
three dimensions. Also, as in DLA, multifractal
behavior is exhibited. At moderately high Peclet
numbers the pattern formed by the dispersing dye in a
two-dimensional porous medium is fractal over the
concentration are self-affine with an anomalously large
roughness exponent. By comparison, we show that the
pattern formed by a dilute ion concentration driven by
an electric field, rather than a flow field, is also
self-affine but with the usual roughness exponent of
0.5.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899