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Magnetic-field effect on thermal convection of a nematic liquid crystal at large Rayleigh numbers
Published online by Cambridge University Press: 31 January 2013
Abstract
We report on near-turbulent thermal convection of a nematic liquid crystal heated from below in a cylindrical cell with an aspect ratio (diameter/height) equal to 0.50 for Rayleigh numbers $2\times 1{0}^{7} \lesssim \mathit{Ra}\lesssim 3\times 1{0}^{8} $ and a Prandtl number of about 355. The Nusselt number $\mathit{Nu}$ as a function of $\mathit{Ra}$ did not differ significantly from that of an isotropic fluid. In a vertical magnetic field $\mathbi{H}$, we found $\mathit{Nu}(H)/ \mathit{Nu}(0)= 1+ a(\mathit{Ra}){H}^{2} $, with $a(\mathit{Ra})= 0. 24{\mathit{Ra}}^{0. 75} ~{\mathrm{G} }^{- 2} $. We present a model that describes the $H$ dependence in terms of a change of the thermal conductivity in the thermal boundary layers due to a field-induced director alignment.
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- ©2013 Cambridge University Press
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Current address: Department of Physics & Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109, USA.
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