Thermocapillary-Coriolis instabilities in liquid bridges

Coriolis effects on thermocapillary instabilities in a liquid bridge of infinite length are investigated. The flow is driven by an imposed temperature gradient along the z direction in a (r,theta,z) rotating frame of reference. When the rotation vector is parallel to the z axis, the return flow, obtained as the unperturbed velocity profile with no rotation, is not modified. In this case, rotation is stabilizing and traveling waves are the prefered mode of instability. If the rotation is orthogonal to the z axis, the base flow is modified and is no longer one-dimensional. Asymptotic methods valid for small rotation are used to calculate the base flow which may become multicellular, both in the radial and azimuthal directions, depending on the Prandtl, Marangoni, and Biot numbers. Linear stability analysis of the new base flow indicates that this type of rotation can be destabilizing while traveling azimuthal waves continue to be the prefered form of convection. Finally, the effect of rotation is studied in a finite length cylinder by direct numerical simulation. (C) 1999 American Institute of Physics. [S1070-6631(99)02009-7].