Nonlinear feedback control of Marangoni wave patterns in a thin film heated from below

Abstract We investigate the effect of nonlinear feedback control on the oscillatory mode of the long-wave Marangoni instability. Thin liquid film heated from below with a deformable free surface atop a substrate of low thermal conductivity is in our spotlight. We apply nonlinear feedback control to change the excitation of convection from subcritical to supercritical, or to stabilize a definite kind of convective pattern. Nonlinear interaction of traveling waves is examined by means of weakly nonlinear analysis within the amplitude equations. The cases of single wave, of pair of counter-propagating waves, and of three-dimensional two-wave patterns are considered. It is shown that by means of quadratic feedback control it is possible to replace a subcritical bifurcation by a supercritical one, as well as extend the stability region of traveling rolls and traveling rectangles and produce additional structures (traveling squares).