2-DIMENSIONAL HYDRODYNAMICAL DESCRIPTION OF A ROTATING NEMATIC SAMPLEIN A MAGNETIC-FIELD

Nematodynamic equations are applied to the description of a cylindrica l nematic sample, rotating around its axis with constant angular veloc ity, in the presence of a perpendicular magnetic field. The system is described by the director orientation n and by the velocity vector v f ields in the cylinder volume. Equations are simplified by considering the director orientation n constrained in a planar section of the cyli nder and by neglecting coupling with the velocity field, which is comp letely determined by the angular speed rate. Boundary conditions for p erfect alignment of the director n perpendicularly to the walls are as sumed. It is shown that a dynamical equation can be obtained which is amenable to numerical analysis for the spatial and time dependence of the director orientation. Transient distributions and stationary solut ions are found and discussed.