DYNAMICS OF HARD-SPHERE SUSPENSIONS

We consider a dispersion of solid spherical particles in an incompressible viscous fluid, and study the dynamics of this two-phase system on the basis of linear response theory. We start from a rest situation, in which the spheres are assumed to be distributed in a disordered configuration. The rest situation is perturbed linearly by small oscillatory applied forces and torques acting on the solute particles, and by an oscillatory force density acting on the fluid. We obtain the mean dynamical response by averaging over an ensemble of rest configurations. The procedure leads to well-defined linear average equations of motion for the two-phase system, and to expressions for the transport coefficients occurring in these equations. We evaluate some of the wave-vector and frequency-dependent transport coefficients of a dilute suspension. © 1990.