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Ericksen number and Deborah number cascade predictions of a model for liquid crystalline polymers for simple shear flow

Phys. Fluids 19, 023101 (2007); doi:10.1063/1.2424499

Published 7 February 2007

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D. Harley Klein and L. Gary Leal
Department of Chemical Engineering, University of California at Santa Barbara, Santa Barbara, California 93106

Carlos J. García-Cervera and Hector D. Ceniceros
Department of Mathematics, University of California at Santa Barbara, Santa Barbara, California 93106
We consider the behavior of the Doi-Marrucci-Greco (DMG) model for nematic liquid crystalline polymers in planar shear flow. We found the DMG model to exhibit dynamics in both qualitative and quantitative agreement with experimental observations reported by Larson and Mead [Liq. Cryst. 15, 151 (1993)] for the Ericksen number and Deborah number cascades. For increasing shear rates within the Ericksen number cascade, the DMG model displays three distinct regimes: stable simple shear, stable roll cells, and irregular structure accompanied by disclination formation. In accordance with experimental observations, the model predicts both ±1 and ±1/2 disclinations. Although ±1 defects form via the ridge-splitting mechanism first identified by Feng, Tao, and Leal [J. Fluid Mech. 449, 179 (2001)], a new mechanism is identified for the formation of ±1/2 defects. Within the Deborah number cascade, with increasing Deborah number, the DMG model exhibits a streamwise banded texture, in the absence of disclinations and roll cells, followed by a monodomain wherein the mean orientation lies within the shear plane throughout the domain. ©2007 American Institute of Physics
History: Received 20 September 2006; accepted 22 November 2006; published 7 February 2007
Permalink: http://link.aip.org/link/?PHFLE6/19/023101/1
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