Rayleigh-Marangoni horizontal convection of low Prandtl number fluids

In this paper we describe the results of the numerical study of the Boussinesq-Navier-Stokes equations for the convection flow in an open top three-dimensional parallelepipedic cavity (4x1x1) driven by a horizontal temperature difference at two opposite vertical walls in presence of thermocapillary effects. Two fluids have been considered with Prandtl number Pr=0.015 and Pr=1, at fixed Rayleigh number, Ra=150; simulations for several values of the Marangoni number (Ma) have been developed in order to detect fully three-dimensional flow configurations. From the analysis of the numerical flows we reach the following conclusions: the increase of the Prandtl number enhances the coupling of the heat and mass transfer phenomena, moreover while at Pr=0.015 a fully three-dimensional behavior is observed at Magreater than or equal to200, at Pr=1 the flow configuration appears clearly three dimensional just at Ma=30; the increase of the Marangoni number induces the appearance of secondary counter-rotating vortices around to the primary one. The values of the Nusselt number at the main stream perpendicular middle plane are provided. (C) 2004 American Institute of Physics.