Evolution of the temperature field at the three-dimensional wave front in a heated liquid film

An experimental study of the transformation of three-dimensional waves into thermocapillarywave structures in the flow of water film on a vertical plate with a heater was carried out using the fluorescent thickness measurement technique and a high-speed infrared recording technique in order to measure the temperature field on the liquid film surface. It was shown that the temperature disturbances occur in the residual layer of the wave film. Then, as the film flows along the heater, temperature inhomogeneities appear transverse to the flow at the three-dimensional wave front; and these inhomogeneities cause deformation of the liquid film and formation of rivulet due to the action of thermocapillary forces.