Thermocapillary instabilities in a laterally heated liquid bridge with end wall rotation
Résumé
The effect of rotation on the stability of thermocapillary driven flow in a laterally heated liquidbridge is studied numerically using the full-zone model of the floating-zone crystal growthtechnique. A small Prandtl number (0.02) fluid, relevant for semiconductor melts, is studied withan aspect ratio (height to diameter of the melt) equal to one. Buoyancy is neglected. A linearstability analysis of three-dimensional perturbations is performed and shows that for any ratio ofangular velocities, a weak rotation rate has the surprising effect of destabilizing the base flow. Bysystematically varying the rotation rate and ratio of angular velocities, the critical threshold andazimuthal wave number of the most unstable mode is found over a wide range of this twoparameter space. Depending on these parameters, the leading eigenmode is a wave propagatingeither in the positive or negative azimuthal direction, with kinetic energy typically localized closeto one of the end walls. These results are of practical interest for industrial crystal growthapplications, where rotation is often used to obtain higher quality crystals.