Solute Transport in Porous Media. Media with Capillaries as Voids

We study solute transport in porous media with periodic microstructures consisting of interconnected thin channels. We discuss a local physical mechanism that occurs at the intersections of channels and promotes mixing of the solute with the solvent (i.e., the host liquid). We identify the parameter regime, where this mechanism is the dominant cause of dispersion, and obtain the effective or macroscopic transport equation that the concentration of solute satisfies when the medium is subjected to a time periodic applied pressure gradient. We conclude with illustrative examples.