Axisymmetric flow structure of thin liquid film under radial temperature difference

Motivated by recent advances in the development of the numerical calculation of fine flow in liquid film, the thermocapillary convection in thin liquid film (1mm) due to temperature difference is studied in this paper. To describe the formation of the thermocapillary convection on gas-liquid interface, a two-phase system was designed, in which the momentum and energy interact directly through the free surface. The finite volume method is used to solve the N-S equation in gas phase and liquid phase, respectively, and the velocity and temperature information are exchanged on the free surface in each time step. The results show that a thermocapillary wave appears in the liquid film when the temperature difference exceeds a certain value. The temperature and velocity fluctuations on the free surface show a radiation shape. The flow field structure is completely symmetrical in the basic state, but it is axisymmetric in the case of oscillation state. The propagation direction of thermocapillary wave is affected by many factors (ambient temperature or inner wall rotation). The wave propagation direction is consistent with the rotation direction when the inner wall rotates. When the angular velocity of inner wall rotation is 8 rad/s, the wave number of thermocapillary wave will be reduced to 3, which is independent of the rotation direction. Graphical abstract