Usefulness of experiments with model fluid for thermocapillary convection-effect of Prandtl number on two-dimensional thermocapillary convection

The floating zone technique is promising to realize large, high-quality cry stals under microgravity. Thermocapillary flow, which is the dominant conve ction in a floating zone under microgravity, has been widely reported in th e literature to be extremely sensitive to the Prandtl number Pr. In the pre sent study, the effect of Pr on steady thermocapillary convection is re-eva luated based on both analytical and numerical solutions. The results indica te that an approximate similarity of temperature and velocity structures in a large Pr range is realized under suitable conditions, fixing the Marango ni number Ma, in steady two-dimensional regime. (C) 2002 Published by Elsev ier Science B.V.