Characteristics of temperature oscillation inthermocapillary convection in rectangular pool

Experimental and numerical results on characteristics of temperature oscillation in a rectangular pool of silicone oil were presented. A thermocapillary-convection controlling system was established in laboratory to study the critical condition and characteristics of temperature oscillation. The applied temperature gradient along the fluid-gas interface drived shear flow along the free surface from hot to cold and a back flow in the underlying layer. When the temperature gradient increases to a critical value, the original steady flow will become unstable to oscillatory flow. And with the deeply increasement of the temperature gradient, the flow will finally transit to the state of chaos. A temperature measurement system, which consists of thermocouple, nano-voltmeter and data-acquiring computer, was used to record the temperature of the liquid dynamically. Critical conditions for different experimental parameters were obtained, and its relationship with Prandtl number and Bond number was discussed in details. In addition, thermocapillary convection in microgravity was simulated; Sloshing of free surface was observed, which is thought to be produced by the interaction between deformation of free surface and flow field.