2014 Linear analysis is used to study the free surface deflections of a fluid heated from below. Numerical calculations provide the regions for which the relief is convex or concave and the influence of the fluid parameters on the deflection. These theoretical results agree very well with the experimental ones obtained previously. J. Physique 46 (1985) 2047-2051 1 DTCEMBRE 1985,

The long-wavelength instability for thermocapillary-driven convection in two dimensions is studied numerically. The system under consideration consists of a horizontal periodical liquid layer bounded from below by a rigid wall and from above by a deformable free surface. The liquid is heated from the bottom wall and cooled from above. The problem can be approximated by the Stokes equation and h...

We here show how evaporation/condensation processes lead to efficient heat spreading along a liquid/gas interface, thereby damping thermal fluctuations and hindering thermocapillary flows. This mechanism acts as an effective thermal conductivity of the gas phase, which is shown to diverge when the latter is made of pure vapor. Our simple (fitting-parameter–free) theory nicely agrees with measur...

Thermoconvective instabilities in a bilayer liquid–gas system with a deformed interface are investigated. In the first part of the work which is devoted to a linear approach, emphasis is put on the role of the upper gas layer on the instability phenomenon. The condition to be satisfied by the gas to remain purely conductive is established. The so-called Oberbeck–Boussinesq approximation is disc...

A linear stability analysis is performed for a horizontal layer of a binary liquid of which solely the solute evaporates into an inert gas, the latter being assumed to be insoluble in the liquid. In particular, a water-ethanol system in contact with air is considered, with the evaporation of water being neglected (which can be justified for a certain humidity of the air). External constraints o...

The viscoelastic fluids are usually the blends of a polymeric solute and Newtonian solvent. In presence temperature gradient, stratification these solutes can take place via Soret effect. Here, we investigate classical Marangoni instability problem for thin film considering this binary aspect fluid. film, bounded above by deformable free surface, is subjected to heating from below solid substra...

Numerical continuation is used to follow branches of steady solutions to the three-dimensional Marangoni–Bénard problem in a zero gravity environment. The upper surface of the fluid is heated by a constant heat flux while the bottom is maintained at a constant temperature. Instability arises due to temperature-dependent surface tension effects but surface deflection is ignored. Containers with ...

The floating zone (FZ) method is one of the growth techniques used to grow single crystal materials. FZ growth is achieved in a containerless environment (without a crucible) by the movement of a molten zone of a solid rod, which forms a free-standing liquid bridge between two solid sections. However, the surface tension along the free surface of the molten zone varies due to temperature and co...