Flow and turbulence generation in a cubic cavity filled by the liquid driven by the gas shear stress over a liquid/gas interface are considered. The coupled gas/liquid flow model is formulated to gain basic understanding of gas flow effects on melt convection, heat and mass transfer during crystal growth by the Czochralski and Directional Solidification methods. As in real crystal growth applications, the gas velocity is assumed to be much higher than the liquid velocity. The gas flow is considered to be laminar for both case of laminar and turbulent liquid convection. The flow of liquid is studied to find conditions of liquid turbulent transition at increasing gas shear stress. A novel dimensionless number is proposed and validated to describe the gas shear stress effect on the liquid flow. Engineering applications to control melt flow structure and oxygen transport during silicon crystal growth are discussed. (C) 2012 Elsevier Ltd. All rights reserved.