Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 25: Diffusion and Dynamics
CPP 25.3: Talk
Wednesday, March 25, 2009, 16:00–16:15, ZEU 160
Dynamic Density-Functional Theory in Flow and Non-uniform Temperature — •Markus Hütter1 and Joseph M. Brader2 — 1ETH Zürich, Department of Materials, Polymer Physics, CH-8093 Zürich, Switzerland — 2Universität Konstanz, Fachbereich Physik, D-78457 Konstanz, Germany
Dynamic density functional theory has proven to be a useful tool for studying the dynamics of colloidal suspensions. Recent attempts have aimed to incorporate flow, non-uniform temperature gradients and hydrodynamic interactions. In this contribution, we take the first steps towards constructing a unified, thermodynamically consistent theory for the complete colloid plus solvent system. First, in order to examine the effect of strongly non-local effects, we formulate a thermodynamically admissible set of evolution equations for a one-component fluid in terms of the densities of mass, momentum, and internal energy. By using coarse-graining techniques, one can examine how long-range interactions on the particle level affect the macroscopic continuum description. The following conclusions emerge. (i) The body forces in the momentum balance have both energetic and entropic contributions in general, but can not be summarized in terms of a free energy-related term. (ii) The thermal conductivity and the viscosity are non-local in space. Second, we consider the colloid plus solvent system. Specifically, we present the evolution equations for the nonisothermal hydrodynamics of the solvent and for the spatial distribution of the colloids. In this way, it is clarified how the latter evolution equation can be extended to flow and nonisothermal situations.