Instability of a two-layer system with deformable interfaces under laser beam heating

New non-standard problem of thermocapillary convection is studied to analyze the flows arising in a two-layer system under action of an intense thermal exposure on the free boundary by a laser beam. Characteristics of the physical experiments are presented. Parameters of the experiments are the ratio of the liquid layer thicknesses, the types of working liquids, the absorption coefficients of media. Special attention is given to the study of the influence of the system geometry when changing the thickness for one of the liquid layers. Theoretical study of the thermocapillary convection includes development of the mathematical model tested on the basis of new physical experiment data and of the effective numerical algorithm to calculate basic characteristics. The occurrence of the decaying oscillations, which first experimentally discovered by the authors, and the evolution of the interfaces and layers are investigated. The results of numerical study of structure and nature of convective flows in the horizontal two-layer liquid – liquid systems of the type "silicone oil – glycerin", and comparison of the experimental and theoretical data allow one to validate the developed mathematical model, to analyze the peculiarities of heat and mass transfer in the two-layer system induced by the action of a local heat source at the free boundary.