The effect of magnetic fields and boundary conditions on the shear flow of nematics

Abstract

The flow of a nematic liquid crystal between plane parallel plates, with one plate moving with uniform velocity relative to the other, is discussed. The apparent viscosity, orientation and velocity profiles are computed for p-azo~yanisole as functions of shear rate and magnetic field for symmetric and asymmetric mole cular alignment at the plates. For symmetric homeotropic boundary condition. a magnetic field applied along the flow direction exhibits a threshold reminiscent of a Freedericksz transition in the hydrostatic case. In general the apparentviscosity for the asymmetric boundary condition is less than that for the symmetric case.