Brownian-dynamics simulation studies of a charge-stabilized colloidal suspension under shear flow

We have carried out Brownian-dynamics simulations of a charged colloidal suspension under oscillatory shear flow with both Couette and Poiseuille velocity profiles. We show that in the ‘‘steady-shear’’ limit, for both of the velocity profiles, the enhancement of the self-diffusion coefficient in directions transverse to the flow shows a crossover from a γ${\mathrm{̇}}^2$ dependence to a γ${\mathrm{̇}}^{1/2}$ dependence as the shear rate γ̇ increases. The magnitude of the enhancement is a function of the interparticle interaction strength. There is a layering tendency in the direction of the velocity gradient for Couette flow, while such a tendency is not that prominent for Poiseuille flow.