Influence of hydrodynamics on many-particle diffusion in 2D colloidal suspensions
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
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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.
© EDP Sciences, Società Italiana di Fisica, and Springer-Verlag, 2004