Experimental study on thermocapillary convection of binary mixture in a shallow annular pool with radial temperature gradient

In this paper, we carried out a series of experiments on the basic characteristics of the thermocapillary convection of binary mixture with moderate Prandtl number in a shallow annular pool which was heated at the outer cylinder and cooled at the inner cylinder at different aspect ratio. Results showed that two-dimensional steady flow, the hydrothermal waves and chaos phenomena will orderly appear with the increase of the thermocapillary Reynolds number. The critical thermocapillary Reynolds number for the onset of the hydrothermal waves decreases with the increase of the aspect ratio and the solute concentration in the range of experiment. The wave number, the propagation angle and the fundamental frequency of the hydrothermal waves decrease monotonically with the increase of the aspect ratio. However, the solute concentration has slightly effect on these characteristic parameters of the hydrothermal waves.