Observation of transition behavior on oscillatory Marangoni flow of Low-Pr number liquid column

An experimental study on thermocapillary convection of low Prandtl number fluid was carried out to understand transition behavior to oscillatory flow. In this experiment, we use molten tin as the working fluid, which Prandtl number is \textit{Pr}$\sim $0.01. The liquid column of molten tin was formed between hot and cold disks in high vacuum chamber and the half-zone configuration was employed. We imposed temperature difference between top and bottom of liquid column to induce a marangoni convection. Temperature distribution at interface between liquid column and cold disk was measured by using several fine thermocouples. As a result, several oscillatory flow patterns were observed. In addition, we compared these results with numerical simulation and estimated the mode stractuers.