STABILIZATION OF UNSTEADY CONVECTIVE FLOWS BY CENTRIFUGATION

A liquid heated from below exhibits temperature fluctuations, characte ristic of an unstable convection regime. When the liquid is placed in the acceleration field of a centrifuge, this convection regime is subj ected to enhanced buoyancy, the Coriolis force and the acceleration gr adient. Flow visualizations in water and temperature measurements in m olten tin and molten germanium are presented, using the large arm cent rifuge of the Laboratoire Central des Ponts et Chaussees at Nantes. Th e transition to a steady state at a certain acceleration threshold, as indicated by the suppression of temperature fluctuations in the three liquids, is accompanied by the formation of a single steady convectiv e roll observed in the visualization experiment. This transition can b e explained by the Coriolis force deflecting the flow streamlines into an organized structure.