We have identified experimentally secondary instability mechanisms that restrict the stable band of wave numbers for ideal hexagons in Bénard-Marangoni convection. We use "thermal laser writing" to impose long wave perturbations of ideal hexagonal patterns as initial conditions and measure the growth rates of the perturbations. For epsilon=0.46 our results suggest a longitudinal phase instabili...

A linear stability analysis of the buoyant-thermocapillary flow in open rectangular cavities with aspect ratios in the range Gamma=1.2 to 8 is carried out for Prandtl number Pr=10 and conditions of previous experiments. The results are in very good agreement with most available experimental data. The energy transfer between the basic and the perturbation flow reveals that buoyancy is not direct...

Rayleigh-Bénard and Bénard-Marangoni instabilities have been studied for roughly a century and have served as prototypes for the transition to temporal chaos as well as spatiotemporal chaos of an initially stationary pattern. Using the Marangoni effect [1,2] with an horizontal temperature gradient to drive the system out of equilibrium, one can observe propagating waves instabilities: hydrother...

We propose a hydrodynamic mechanism, based on the Marangoni flow, to describe growth instabilities of liquid-condensed islands in the supercooled liquid-expanded phase of two-dimensional Langmuir monolayers. This Marangoni instability is intrinsic to Langmuir monolayers and is not controlled by the expulsion of chemical impurities from the liquid-condensed phase. The hydrodynamic transport of t...

Recent experimental and theoretical efforts have revealed the existence of a fingering instability at the moving front of thin liquid films forced to spread under gravitational, rotational or surface shear stresses, as for example by using the Marangoni effect. We describe how the presence of a precursor film in front of the spreading macroscopic film, whether it is by prewetting the substrate ...

The three-dimensional instability of the thermocapillary convection in cylindrical undeformable floating zones heated laterally is studied numerically. Different types of the boundary conditions, including radiation heating, linearized radiation and prescribed heat flux are used in the calculation. Stability diagrams showing the Prandtl number dependence of the critical Marangoni numbers that r...