Oscillatory Marangoni convection in variable-viscosity fluid layer: The effect of thermal feedback control

The effect of a feedback control strategy on the onset of oscillatory convection in an infinite horizontal layer of fluid with temperature-dependent viscosity is investigated theoretically using linear stability analysis. It is shown that small viscosity variations stabilizes the fluid layer. Large controller gains, large viscosity variations, and high surface tension, however, promote the onset of overstability leading to oscillatory motions.