Steady flow of a nematic liquid crystal in a slowly varying channel

We consider steady, two-dimensional flow of a thin film of a nematic liquid crystal between a fixed blade of prescribed shape and a planar substrate moving parallel to itself with a constant velocity. We use a combination of analytical and numerical techniques to analyse the Ericksen-Leslie equations governing the fluid velocity and pressure and the director orientation when both the aspect ratio of the slowly varying channel formed between the blade and the substrate and the distortion of the director field are small. We demonstrate that, in the limit of small orientational elasticity, orientational boundary layers occur close to the substrate and close to the blade, and that, in addition, an orientational internal layer may also occur within which the director orientation changes from + Θ0 to − Θ0, where Θ0 is the flow--alignment angle.