Abstract
Two convections can be induced by a temperature inhomogeneity in a floating zone. One is a buoyancy driven convection caused by a thermal variation in the liquid density. The other is a surface tension driven convection (Marangoni convection) caused by a thermal variation in the liquid surface tension. Combined steady convections in a cylindrical floating zone were computationally obtained for various combinations of the Grashof numbers and Reynolds numbers due to the Marangoni convection. The Marangoni convection was dominant over the buoyancy driven convection if the zone length was shorter than a critical zone length, and vice versa. The critical zone length on earth was calculated for various liquids.