Dispersion in oscillatory Couette flow with sorptive boundaries

A multiple-scale method of averaging is applied to the study of dispersion in oscillatory Couette flow where the solute may undergo reversible sorptive phase exchange with the boundary walls. On assuming that the oscillation period and the sorption reaction time are comparable with the transverse diffusion time, which is much shorter than the axial transport time scales, an effective advection-dispersion transport equation in terms of the mean concentration is deduced at the second order. Analytical expressions are obtained for the two dispersion coefficients due to the steady and oscillating components of the Couette flow, incorporating the coupling effects between the flow oscillation, sorption kinetics, and the retardation due to phase partitioning. [PUBLICATION ABSTRACT]