Key words: Natural convection, finite volume, parallelepiped, k-epsilon.

Abstract: The heat transfer by convection is, so far, a basic principle of many industrial applications. This study led to the analysis of turbulent convection. Ra > 10⁹ in a rectangular three-dimensional cavity filled with air, the two opposite vertical walls are differentially heated a constant temperature at cold wall and the heat flux at the hot wall, the other walls are hot wall except ceiling wall is cold according to fig. 2. The finite volume method has been used to discretize the equations of flow in turbulent convection. The model of turbulence used is κ-ε. The results obtained are suitable, because they show that for a number of Pr = 0.71 and while varying the heat flow, generating consequently a great influence on the transfer of heat inside the field of study, the numerical results of the heat flux at the hot wall are over predicted. The strong influence of the undulation of the cavity and its orientation is well shown, and the release of the instability due to the interactions of the swirling structures with the boundary layer.