title: Dynamics of a disc in a nematic liquid crystal.
abstract: We use lattice Boltzmann simulations to study the dynamics of a disc immersed in a nematic liquid crystal. In the absence of external torques, discs with homeotropic anchoring align with their surface normal parallel to the director of the nematic liquid crystal. In the presence of a weak magnetic field a ferromagnetic disc will rotate to equilibrate the elastic torque due to the distortion of the nematic director and the magnetic torque. When the magnetic field rotates the disc so that the angle θ between normal to the surface of the disc â and director of the liquid crystal n[combining circumflex] becomes greater than π/2, the disc flips around the axis perpendicular to the rotation axis so that â sweeps through π radians. An analysis of this behaviour was performed. In particular, we look at the impact of the disc thickness and edges on defect creation and the flipping transition. We also analyse the importance of backflow.
authors.affiliation: Department of Applied Mathematics, The University of Western Ontario, London, Ontario N6A 5B8, Canada. aantipov@uwo.ca.
authors.forename: Alena
authors.initials: A
authors.lastname: Antipova
authors.affiliation: Department of Applied Mathematics, The University of Western Ontario, London, Ontario N6A 5B8, Canada. aantipov@uwo.ca and Department of Physics and Astronomy, The University of Western Ontario, London, Ontario N6A 5B8, Canada. cdennist@uwo.ca.
authors.forename: Colin
authors.initials: C
authors.lastname: Denniston