Rheologica Acta

, Volume 39, Issue 3, pp 215–222

The undulation instability in layered systems under shear flow – a simple model

  • Günter K. Auernhammer
  • Helmut R. Brand
  • Harald Pleiner
ORIGINAL CONTRIBUTION

DOI: 10.1007/s003970000074

Cite this article as:
Auernhammer, G., Brand, H. & Pleiner, H. Rheol. Acta (2000) 39: 215. doi:10.1007/s003970000074

Abstract

 We propose a generalization to the usual hydrodynamic description of smectic A liquid crystals: The layer normal and the director are assumed to be coupled elastically to each other in such a way that they are parallel in equilibrium. If a sample with the layers parallel to the plates is sheared, our generalization leads in first order to a flow alignment of the director in the flow direction without perturbing the layers. Due to this tilt of the director the layers have a tendency to reduce their thickness. A linear stability analysis shows that the layers accommodate this tendency above a critical shear rate by developing undulations with a wave vector parallel to the vorticity direction of the shear flow.

Key words Shear flow Smectic A liquid crystals Undulation instability Layered systems 

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Günter K. Auernhammer
    • 1
  • Helmut R. Brand
    • 1
  • Harald Pleiner
    • 2
  1. 1.Theoretische Physik III Universität Bayreuth 95440 Bayreuth, Germany e-mail: btpb03@theo.phy.uni-bayreuth.deDE
  2. 2.Max-Planck-Institut für Polymerforschung 55021 Mainz, GermanyDE

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