Regensburg 2007 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 14: Fluid dynamics II
DY 14.1: Talk
Tuesday, March 27, 2007, 11:15–11:30, H2
Boudany effects in fluids with internal orientational degree of freedom. — •Sebastian Heidenreich1, Patrick Ilg2, and Siegfried Hess1 — 1Technische Universität Berlin, D-10623, Germany — 2ETH Zürich, Wolfgang-Pauli-Str. 10, 8093 Zürich
In nano- and microfluidics the length scales of devices are comparable to the molecular lengths and fluid-wall interactions become
significant for the flow behavior. In our contribution we consider fluids with an internal orientational degree of freedom. We use the
relaxation equation [1], an amended Landau-de Gennes potential [2] to model the spatially inhomogeneous orientational dynamics and the
momentum balance equation to couple the velocity on the orientation. In order to model fluid-wall interactions we use different boundary
conditions on the alignment tensor (anchoring) as well as on the alignment flux tensor (consequences of irreversible thermodynamics [3]).
We show analytically that for stationary flows (plane Couette and Poiseuille flows) in the isotropic phase boundary conditions on the
alignment flux tensor lead to an apparent velocity slip. Furthermore the interplay between the flow velocity and the orientation dynamics in the
nematic phase under consideration of the different boundary conditions is presented.
S. Hess, Z. Naturforsch. 30a, 728, 1224 (1975)
S. Heidenreich, P.Ilg and S. Hess, Phys. Rev. E 73, 061710 (2006)
L. Waldmann, Z. f. Naturf. 22a, 1269 (1967); L. Waldmann and H. Vestner, Physica 99A, 1 (1979);
S. Hess and H. M. Koo, J. Non-Equilibrium Thermodyn. 14, 159 (1989)