Temperature pulsations and thermocapillary effects on the surface of a wavy heated liquid film

The temperature pulsations and wave characteristics in water film flow along a vertical plate with a heater are investigated. Using an infrared scanner, the temperature field on the film surface is measured for various heat flux densities on the heater. Experimental data on the variation of the temperature with time on a local segment of the liquid film surface during wave transmission are obtained. In the absence of a heat flux the data obtained are in good agreement with the results of other researchers for an isothermal liquid film. When the down-flowing liquid is heated, the thermocapillary forces lead to the formation of rivulets and a thin film between them. It is shown that in the inter-rivulet zone the relative wave amplitude increases due to the action of the thermocapillary forces.