Hydrodynamic interactions and the viscosity of suspensions of freely moving spheres

A computational method aimed at calculating the hydrodynamic interactions between spherical particles, within the framework of the ‘‘creeping-flow’’ approximation, is developed further. The basic fluid equations for a system with periodic boundary conditions have been rederived, paying particular attention to possible divergences in the fluid velocity field. Numerical results have been obtained for the viscosity of a suspension of freely moving hard spheres over a range of solid densities from the dilute limit to near the hard-sphere freezing transition.