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Fluid Dynamics Seminar

Monday, April 5, 2010, 4:00 PM
Cullimore Hall 611
New Jersey Institute of Technology

Symmetry breaking and bifurcations in rigid rod nematic suspensions

Arvind Gopinath

Department of Mechanical Engineering, MIT

Abstract

Rod-like nematic liquid crystals appear in various guises in biology (a tobacco mosaic virus suspension is a nematic solution for instance) and in technology (such as in liquid crystal displays). Consequently these complex fluids have been the subject of intense study over the last few decades. The investigations have shed light on structure formation as well as dynamic response under both equilibrium and non-equilibrium conditions. However, many questions still remain to be clarified. For example, the influence of imposed flow or the role of confining boundaries is still to be understood clearly.

I will present an overview of recent theoretical and computational studies on the effect of weak fields on a canonical model for a nematic crystal - a suspension of high aspect ratio, Brownian hard rods. We will first review the equilibrium phase (bifurcation) diagram for a homogeneous suspension focusing on the symmetries possessed by the different solutions. I will then describe how this picture is disturbed in two scenarios - first, when the fluid is subject to a weak homogeneous shear and second, when the rods are polar resulting in loss of fore-aft symmetry. The focus will be on the relationships between new solutions and the symmetries broken in the process of emergence. I will conclude with a description of current work on understanding spinoidal decomposition in non-homogeneous hard rod systems.