Hydrodynamic interactions and diffusion in concentrated particle suspensions

Abstract

We extend our earlier Langevin treatment of the dynamics of interacting Brownian particles to include hydrodynamic interactions, couplings of the particles' motions transmitted through the solvent. We consider the short-time behaviours of the self and full dynamic structure factors and a particle's mean-square displacement. Effects due to the finite propagation time of hydrodynamic interactions (‘long-time tails’) are also discussed briefly. Finally, experimental measurements of the short-time self-diffusion coefficient of a particle in a concentrated suspension are reported. In agreement with recent theories, these experiments demonstrate the importance of irreducible many-particle effects.