CELL NUMBER SELECTION IN ELECTROHYDRODYNAMIC CONVECTION IN LIQUID-CRYSTALS

Results of an experimental investigation into a pattern selection mech anism in electrohydrodynamic flow in a nematic liquid crystal device a re presented. The apparatus consists of a small aspect ratio cell so t hat only a few spatial modes are activated. The initial bifurcation to cellular flow is found to be disconnected, and the ensuing cell numbe r selection process is in agreement with the mechanism proposed by Ben jamin for Navier-Stokes flows. The results point to a greater generali ty of this mechanism, since the flow we consider here is of a complex fluid on a microscopic length scale.