title: Influence of hydrodynamics on many-particle diffusion in 2D colloidal suspensions.
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 DT(rho)/D0 and DC(rho)/D0 respectively, where D0 is the single-particle diffusion coefficient, as a function of the density of the colloids rho. At low Schmidt numbers Sc - 1, we find that hydrodynamics has essentially no effect on the behaviour of DT (rho)/D0. At larger Sc, DT (rho)/D0 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.
authors.affiliation: Laboratory of Physics - Helsinki University of Technology, FIN-02015 HUT, Finland. efalck@cc.hut.fi
authors.forename: E
authors.initials: E
authors.lastname: Falck
authors.forename: J M
authors.initials: JM
authors.lastname: Lahtinen
authors.forename: I
authors.initials: I
authors.lastname: Vattulainen
authors.forename: T
authors.initials: T
authors.lastname: Ala-Nissila
mesh_terms: D003102:Colloids / Q000737:chemistry; D045424:Complex Mixtures / Q000737:chemistry*; D003198:Computer Simulation; D004058:Diffusion; D046911:Macromolecular Substances; D044085:Microfluidics / Q000379:methods*; D008956:Models, Chemical; D015233:Models, Statistical; D009038:Motion; D013535:Suspensions / Q000737:chemistry*
chemical_list: D003102:Colloids; D045424:Complex Mixtures; D046911:Macromolecular Substances; D013535:Suspensions