NUMERICAL-SIMULATION OF SURFACE-TENSION DRIVEN FLOWS IN LIQUID BRIDGES

The paper deals with surface tension driven flows, induced by imposed temperature differences, in axisymmetric liquid bridges. This configur ation is connected to processes of crystal growth from melt by the flo ating zone method. The field equations are solved via a two-dimensiona l, unsteady, finite difference numerical code in terms of vorticity, s tream function and temperature. The Poisson equation for the pressure field is solved, by using Briley's correction, and the free surface sh ape is computed under the assumption of small capillary number. The fl ow field structure and behaviour are discussed in terms of non-dimensi onal characteristic numbers and the aspect ratio A = R/L, with R and L , respectively, the radius and the length of the bridge. Stream lines, isotherms, velocity profiles, surface shapes are given and discussed. In particular, we report the maximum of the surface velocity, the max imum of the surface deformation and the bulk heat transfer coefficient (Nusselt number) as functions of the aspect ratio.