Experimental study on oscillatory thermocapillary convection

Results of an experimental study of the transition from steady to oscillatory flow in a liquid bridge of a half-floating zone are presented. The distribution of the critical Marangoni numbers, described by the onset of oscillations at the free surface of the liquid bridge, was measured by two noncontact methods. The results obtained are found to be in agreement with the predictions of Rayleigh's instability theory. The experiments performed in a small liquid bridge, with the Bond number much less than 1, can be used for the simulation of a microgravity environment.