Regensburg 2007 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 14: Fluid dynamics II

DY 14.1: Vortrag

Dienstag, 27. März 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)