Observation of First Transition of Marangoni Convection in Low Prandtl Liquid Bridge

Abstract

The experimental study on thermocapillary convection of low Prandtl number fluid was carried out to observe the first transition. The half-zone liquid bridge of molten tin was used as a test configuration. In order to detect very slight temperature changes, the temperature measurement system was improved. It was able to be experimentally detected that the axisymmetric steady flow changes to three-dimensional steady one with increasing the temperature difference between hot and cold disks. At higher temperature difference, oscillatory transition was also observed. Aspect ratio dependence on critical Marangoni number was compared with numerical results. The experimental result of a first critical Marangoni number agreed very well with numerical one.