3D effects in numerical simulations of convective flows in cubical open cavities

Buoyancy-driven flows established in open cubical cavities are investigated. Three-dimensional, laminar, transitional and turbulent simulations are obtained, considering both uniform wall temperature and uniform heat flux heating. Aiming the study of 3D effects, results are compared with those previously obtained for 2D situations. To take into account the effects of the variable properties of air, it is assumed that both thermal conductivity and the viscosity depend on temperature, with the density estimated from the state equation. The low-Reynolds k-omega turbulence model is employed to simulate the transitional or fully turbulent flow. The average Nusselt number and the dimensionless mass flow rate have been obtained for Rayleigh numbers ranging 10(6) <= Ra-H <= 10(12). The results obtained taking into account variable properties effects are compared with those calculated assuming constant properties and the Boussinesq approximation. In addition, the influence of considering an internal wall (adiabatic or isothermal) is also studied, as well as the influence of the slope of external heated wall. (C) 2013 Elsevier Masson SAS. All rights reserved.