ACTIVE CONTROL OF RAYLEIGH-BENARD CONVECTION

We report on stabilizing the unstable no-motion state in a moderate as pect ratio one-dimensional Rayleigh-Benard convection experiment. A li near proportional control algorithm uses shadowgraphic convection imag es to determine heat flux perturbations which are applied to the lower boundary by a network of local heaters. We show that simple linear co ntrol stabilizes the otherwise unstable no-motion (conduction) state o ver a substantial range of supercritical Rayleigh numbers. (C) 1997 Am erican Institute of Physics.