Effect of liquid bridge shape on the oscillatory thermal Marangoni convection

The effect of liquid bridge shape on the instability and associated oscillation mode of Marangoni convection due to the temperature gradient along the free surface is experimentally studied. Although the onset condition of oscillatory state is known to depend on the liquid bridge shape, this effect is not completely understood yet. Onset conditions are measured for various combinations of the aspect ratio (AR) and the volume ratio (VR) of liquid bridges. It is found that the convection becomes most stabilized at a certain combination of AR and VR and also that the oscillation mode changes at this most stabilized condition. To account for the effects of AR and VR in a simple way, a new dimensionless parameter SDR (i.e., the ratio of the surface length to the neck diameter) is proposed. It is shown that all the onset conditions measured presently are well correlated with SDR