longitudinal dispersion in nonuniform isotropic porous media

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CHAPTER 2
LITERATURE REVIEW
Transport phenomena during flow through porous media have been an
active topic of research over the past 30 years. During this time,
several distinct classes of porous media models have been developed.
Considering the geometrical complexity of a porous medium, a crucial
element in any model is the conceptual representation of the pore
spaces. The different idealizations used to model a porous medium vary
widely, ranging from simple capillary models which bear little
resemblance to a porous medium to statistical models in which the
complex geometry is modeled through probability density functions.
The results of this effort at modeling solute transport 1n porous
media are encouraging but far from complete. The problem in this type
of modeling appears to be a reluctance to use more detailed information
on the pore structure to define the medium. This reluctance is
understandable for two reasons:
1. It is difficult to incorporate microscopic structural information
into a solute transport model, particularly if one is interested in
eventually using a macroscopic model such as the advection-diffusion
equation.
2. Pore structural information 1S difficult to obtain and interpret.
Despite the limitations of the theoretical models reviewed here,
they provide reasonably accurate predictions for mass transport 1n