Convective Auto-Oscillations Near a Drop–Liquid Interface in a Horizontal Rectangular Channel

The concentration convection in an isothermal liquid near a drop (or an air bubble) clamped between the vertical walls of a horizontal channel is studied numerically within the framework of two simple mathematical models: with and without the surface phase at the drop–liquid interface formed by adsorption/desorption process. The interaction between the buoyancy and the Marangoni convective flows is responsible for the onset of auto-oscillation regime. Such oscillations have been experimentally investigated in other works. In our numeric experiments, more than 20 outbursts of the Marangoni convection were observed. The surfactant distributions obtained numerically at different oscillation phases agree well the experimen tal data.