Nonlinear Buoyant‐Thermocapillary Waves in Multilayer Systems

Abstract

The interfacial convection in multilayer systems is a widespread phenomenon that is of great importance in numerous branches of technology, including space technologies, chemical engineering, coating, etc. The most well-known modern engineering technique that requires an investigation of convection in multilayer systems is the liquid encapsulation crystal growth technique [1], [2] used in space labs missions. Another important problem is the droplet-droplet coalescence, where Marangoni convection in the interdroplet film can considerably affect the coalescence time during extraction [3]. Simultaneous interaction of interfaces with their bulk phases and with each other was studied for heating from below and from above, as well as in the case of the horizontal temperature gradients (see [4] and references therein). A scientific interest in such systems is due to the fact that the interfacial convection is characterized by a variety of physical mechanisms and types of instability. In the present work, the nonlinear buoyant–thermocapillary flows in three superposed horizontal liquid layers bounded by two solid planes and subjected to a temperature gradient directed along the interfaces, are investigated (for details, see [5]). The nonlinear simulations of the wavy convective regimes for the system silicone oil 1 – ethylene glycol – fluorinert FC75, are performed. Two types of boundary conditions, periodic boundary conditions and rigid heat – insulated lateral walls, are considered. The shape and the amplitude of the convective flows are studied by the finite-difference method. The details of the numerical method can be found in the book by Simanovskii and Nepomnyashchy [6].