Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 22: Posters I

DY 22.7: Poster

Mittwoch, 28. März 2012, 17:00–19:00, Poster A

Effects of hydrodynamic interactions in heterogeneous nucleation of colloids — •Dominic Röhm and Axel Arnold — Institute for Computational Physics, Universität Stuttgart, 70569 Stuttgart, Germany

Nucleation, the early stage of crystal growth, is still a rather poorly understood process. We investigated the heterogeneous nucleation in a colloidal model system near a wall using Molecular Dynamics computer simulations. In our coarse-grained simulations, the particles interact via a screened Coulomb (Yukawa-) potential representing charged colloids in water. Our focus lies on the influence of the hydrodynamic interaction, which is often neglected, since nucleation is considered as a quasi-static process. However, recent experiments have shown, that the kind of thermalization of the sample has a drastic influence on the nucleation rate.

In our simulations, we incorporated hydrodynamic nteractions by coupling the particles to a lattice fluid. Since the computation of the hydrodynamic interaction is still orders of magnitude more expensive than classical interactions, we have recently enabled our MD simulation software ESPResSo to employ GPUs for the calculation of the lattice fluid. By this, we can investigate systems, that previously required a small computer cluster, using a single GPU. Using a cluster equipped with GPUs, allows us to systematically investigate the influence of hydrodynamics on the heterogeneous nucleation, and explain why laminar flow conditions, can lead to enhanced nucleation by pre-ordering.