Abstract:
The transformation of hydrodynamic perturbations into thermocapillary-wave structures in a locally heated water film flowing down a vertical plate has been experimentally studied using a high-speed IR imager for monitoring the temperature field and a fluorescent technique for determining the liquid film thickness. It is established that a three-dimensional (3D) front of the hydrodynamic wave acquires inhomogeneous temperature profile, which leads to a deformation of the liquid film under the action of thermocapillary forces and results in the formation of rivulets. Distances between the 3D waves and rivulets are determined as functions of the heatflux density. The experimental data are compared to the theoretical results.