Bénard–Marangoni convection in a strongly evaporating fluid

We consider a volatile fluid with a free surface. If the evaporation rate is large enough, the temperature gradient caused by latent heat may destabilize the conducting, motionless state and convection sets in. The conditions for instability are computed by means of a linear stability analysis of the full two-layer system. A 3D numerical integration of the one-layer system with a very large effective Biot number shows the evolution of squares as a secondary bifurcation rather close above onset. Time dependent, chaotic states are obtained for larger temperature gradients. The influence of a large Biot number on wave length selection and pattern morphology is studied.