Numerical simulation of Marangoni flow in partially confined half-zone liquid bridge of low-Prandtl-number fluids

Direct numerical simulation using a finite difference method was done to reveal the fundamental characteristics of the flow in a half-zone liquid bridge of low Prandtl number fluids with the free surface partially confined by oxide films (non-slip adiabatic rigid walls). The critical Marangoni number Ma(c1) was calculated for several geometries, which are determined by the free surface ratio (xi = L-w/L, L-w: length of the free surface, L: height of the whole liquid bridge) and the axial position of the free surface. When the oxide film exists between the free surface and the cold disc, the flow separates from the oxide film, and a weak cell with a counter flow arises near the cold disc. An axisymmetric flow exhibits a direct transition to an oscillatory flow, when the free surface ratio is sufficiently small and free surface was located away from the cold disc. (C) 2003 Elsevier B.V. All rights reserved.