Comparison between the Diffusion and Relaxation Models of Longitudinal Dispersion
The properties of the relaxation (wave) model of longitudinal dispersion are considered. The diffusion and relaxation models of longitudinal dispersion are compared. It is shown that, depending on its coefficients, the relaxation model can be assigned to two main classes and one intermediate class provided the boundary conditions for the model equations are correctly formulated. New equations are obtained, whose solutions are asymptotically close to the solutions of the diffusion model.