Abstract
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 use nonlinear relaxation equations for the alignment tensor 1,2 to model the spatially inhomogeneous orientational dynamics of nematic liquid crystals, constitutive
equations for the pressure tensor 3 and the momentum balance equations to couple the
velocity on the orientation. In order to model fluid-wall
interactions we use boundary conditions on the alignment tensor
(strong anchoring) as well as on the alignment flux tensor
(consequences of irreversible thermodynamics 4). For stationary
flows in the isotropic phase an analytical analysis shows an
apparent velocity slip as a consequence of the boundary conditions
on the alignment flux tensor 5. Here we present results from
numerical investigations on the interplay between the flow velocity and
the orientational dynamics in the nematic phase under the
consideration of different boundary conditions. \\
1) S. Hess, Z. Naturforsch. 30a, 728, 1224 (1975)\\
2) S. Heidenreich, P.Ilg and S. Hess, Phys. Rev. E 73, 061710 (2006)\\
3) C. P. Borgmeyer and S. Hess, J. Non-Equilibrium
Thermodynamics,20, 662, 1224 (1988)\\
4) 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)\\
5) S. Heidenreich, P.Ilg and S. Hess, appears in Phys. Rev. E.
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