Thermocapillary Effects in Nonisothermal Liquid Film at High Reynolds Numbers

The temperature and wave characteristics of the water film flowing down a vertical plate with a heater at Re = 300 are studied. The field of film thicknesses at different heat flux values was measured using the fluorescence method. The temperature field on the film surface was measured by an infrared scanner. The experimental data were obtained for variations in temperature over the liquid film surface with time during the propagation of waves. When the falling liquid is heated, the thermocapillary forces lead to formation of rivulets and a thin film between them. Averaging of measurements allowed the value of the transverse film deformation to be determined. Two mechanisms of influence of thermocapillary forces on the motion of the wavy liquid film are marked. For the first time, the exhibition of such a strong thermocapillary effects is revealed in the heated liquid film at high Reynolds numbers.