Exact computation of the mean velocity, molecular diffusivity, and dispersivity of a particle moving on a periodic lattice

A generic scheme was developed for computing the mean velocity vector ̄U* and dispersivity dyadic ̄D* from lattice models of transport in spatially periodic arrays of obstacles, the latter representing simple models of gel electrophoresis. The resultant scheme constitutes the only analytical method available at the present time for correctly computing the dispersivity dyadic from lattice Monte Carlo models for finite fields.