A numerical investigation into thermal instabilities in homeotropic nematics heated from below

Abstract

This paper employs continuum theory to examine the onset of a particular type of cellular thermal instability in a sample of nematic liquid crystal confined between two infinite, horizontal flat plates when subjected to a vertical temperature gradient. We consider the case in which the anisotropic axis is initially uniformly aligned perpendicular to the plates. Using Chebyshev polynomials, accurate numerical solutions for the critical temperature gradient are obtained and the variation of this quantity with a uniform magnetic field applied vertically across the plates is investigated. In particular we obtain the value of the magnetic field at which the nature of the instability changes from an oscillatory type to a stationary one.