Computational study of turbulent natural convection in a side-heated near-cubic enclosure at a high Rayleigh number

A computational study of turbulent natural convection in a side-heated near -cubic enclosure at a high Rayleigh number (Rn = 4.9 x 10(10)) is performed , aimed at gaining a better insight into the Bow pattern, particularly in t he corner regions. Two types of thermal boundary conditions are applied at the horizontal walls: adiabatic and isothermal. Also, two kinds of lateral vertical walls are studied, corresponding to different experimental approxi mations of adiabatic conditions: the first by insulation and the second by imposing a stratified wall heating. The latter conditions ensure better flo w two-dimensionality, with the temperature stratification on the vertical w alls close to that expected in the parallel mid-plane. Computations are per formed with both a two-dimensional (2D) and three-dimensional (3D) code usi ng a low-Reynolds-number differential second-moment stress/flux closure and the related k-epsilon model (KEM) simplification. The numerical computatio ns show that the second-moment closure (SMC) is better in capturing thermal three-dimensionality effects and strong streamline curvature in the corner s. The KEM, however, still provides reasonable predictions of the first mom ents away from the corners. (C) 2001 Elsevier Science Ltd. All rights reser ved.