Three‐Dimensional Solutions for Solute Transport in an Infinite Medium With Mobile and Immobile Zones

Abstract

Tailing of breakthrough responses, which has been experimentally observed during flow through porous media, can be modeled by dividing the porous medium into regions of mobile and immobile water, and coupling the advective‐dispersive solute transport equation with expressions to describe diffusional transfer between the two regions. Three‐dimensional solutions to this coupled set of partial differential equations with infinite boundary conditions are derived by applying the Laplace transform to the equations with respect to time, and the Fourier transform with respect to space. The solutions presented herein may be useful in applying the two‐region models to field settings.