Fokker-Planck-Equation Approach to Flow Alignment in Liquid Crystals

Abstract A nonlinear inhomogeneous relaxation equation for the alignment tensor is derived from a Fokker-Planck-equation for the orientational distribution function where torques exerted by a molecular field and by the gradient of the flow velocity are taken into account. Phenomenological coefficients characterizing the flow alignment in the isotropic and in the nematic phases are related to molecular parameters.