Eur. Phys. J. E (2004) 13: 267-275
https://doi.org/10.1140/epje/i2003-10075-9

Influence of hydrodynamics on many-particle diffusion in 2D colloidal suspensions

¹ Laboratory of Physics - Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT, Finland
² Helsinki Institute of Physics - Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT, Finland
³ Department of Physics, Brown University, Box 1843, RI 02912-1843, Providence, USA

^* e-mail: efalck@cc.hut.fi

Abstract

We study many-particle diffusion in 2D colloidal suspensions with full hydrodynamic interactions through a novel mesoscopic simulation technique. We focus on the behaviour of the effective scaled tracer and collective-diffusion coefficients and , respectively, where D ₀ is the single-particle diffusion coefficient, as a function of the density of the colloids . At low Schmidt numbers , we find that hydrodynamics has essentially no effect on the behaviour of . At larger Sc, seems to be enhanced at all densities, although the differences compared to the case without hydrodynamics are rather minor. The collective-diffusion coefficient, on the other hand, is much more strongly coupled to hydrodynamical conservation laws and is distinctly different from the purely dissipative case without hydrodynamic interactions.