Berlin 2005 – scientific programme

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DY: Dynamik und Statistische Physik

DY 34: Poster

DY 34.69: Poster

Monday, March 7, 2005, 15:30–18:00, Poster TU D

Particle diffusion in fluid flow — •Michael Schindler, Peter Talkner, Marcin Kostur, and Peter Hänggi — Theoretische Physik I, Institut für Physik, Universität Augsburg

We present results showing the diffusive transport of advected particles in a fluid flow field. Such behaviour is important e.g. for large molecules in biological cells but also in more technical applications like “planar fluidics” [1] on partially wetting substrates. The drift term in the corresponding Fokker-Planck equation is taken to be a solenoidal velocity field given as the solution of the stationary Stokes equation. In order to find non-trivial distributions of the particle’s position in the fluid we have to embed into the Fokker-Planck equation the fact that the particles are of finite size. The boundary conditions of the Stokes equation are determined by the considered systems. Especially in the limit of small fluid domains the strong surface tension at free surfaces dominates the functional form of the velocity field.

[1] Z. Guttenberg et al., Flow profiling of a surface acoustic wave nanopump, Phys. Rev. E 70, xxxxx (2004) in press; arxiv:cond-mat/0405199.