Abstract
Two nematic liquid crystals are studied in a torsional shear flow apparatus. The nematics are MBBA (neg.diel.anisotropy) and 5CB (pos.diel.anisotropy). The director align in the shear at a certain angle θn to the normal to the flow direction, except at two boundary layers near the surfaces. The influence of an electric field on the flow alignment angle and on the size of the boundary layers is studied both theoretically and experimentally.