要約

This paper concerns a numerical study of three-dimensional laminar mixed convection within a liquid flowing in a horizontal channel heated uniformly from below. The upper surface is free and assumed to be flat. The coupled Navier-Stokes and energy equations are solved numerically by the finite volume method taking into account the thermocapillary effect (Marangoni effect). When the forces induced by the currents of natural and forced convection are of the same order of magnitude (for Richardson number Ri=Ra/(Pr.Re²)=O(1)), the results show the development of instabilities in the form of steady longitudinal convective rolls similar to those encountered in the Poiseuille-Rayleigh-Bénard flow. The number and spatial distribution of these rolls along the channel depend on the flow conditions. The objective of this work is to study the influence of parameters such as the Biot numbers and the aspect ratio of the channel on the flow patterns and heat transfer characteristics. The effects variations in the surface tension with temperature gradients (Marangoni effect) are also considered.