Dresden 2011 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 43: Soft Matter

DY 43.5: Talk

Friday, March 18, 2011, 11:15–11:30, ZEU 118

Phase diagram and orientational dynamics of nematic liquid crystals under shear flow: A numerical bifurcation analysis. — •David A. Strehober and Sabine H. L. Klapp — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany

We study the nonequilibrium dynamics of rodlike nematic polymers under shear flow. Starting from a mesoscopic description involving the alignment tensor [1][2], we investigate the rheological phase diagram with respect to the shear rate and tumbling parameter. The dynamics of the alignment tensor is described by five coupled differential equations. We employ numerical continuation methods, specifically the freely available software package MATCONT [3], to find the boundaries between different dynamic states. We recover the results that were obtained via direct integration [4] of the set of differential equations for the alignment tensor. On top of that, we are able to make statements about the nature of the bifurcations, and how orientational modes, i.e. Kayaking Wagging or Tumbling, are born. We conclude the talk with a discussion of the role of temperature.
[1] S. Hess, Z.Naturforsch. A 31a, 1034 (1976)
[2] M. Doi, J.Polym. Sci., Polym. Phys. Ed. 19, 229 (1981)
[3] A. Dhooge, W. Govaerts, and Yu. A. Kuznetsov., ACM Trans. Math. Softw. 29, (2003)
[4] S. Grandner, S. Heidenreich, S. Hess and S. H. L. Klapp, Eur.Phys.J. E 24, 353 (2007)