Impact of Gravity on the Flow Pattern in a Locally Heated Two-Layer System

Abstract

Problem of thermocapillary convection is studied to analyze peculiarities of the flows arising in a gas–liquid system under action of an intense local thermal exposure. The “stream function–vorticity” formulation of the Navier–Stokes equations in the Boussinesq approximation is used to describe the fluid flows. The kinematic and dynamic conditions on the free boundary are stated in terms of tangential and normal velocities, while temperature conditions at the lower or upper boundary of the system take into account the presence of finite size heaters. Special attention is given to the study of the influence of the gravity intensity on the dynamics of heat and mass transfer in fluid layers and character of the interface deformations. Theoretical study of the thermocapillary convection includes development of the mathematical model and effective numerical algorithm. The results of numerical study of features of convective flows in the cavity being in the terrestrial or microgravity conditions and of the evolution of the interface allow one to validate the developed mathematical model, and to specify dominant mechanisms determining the flow regimes.