Coupling of turbulent natural convection with radiation in an air-filled differentially-heated cavity at Ra = 1.5 × 109

This paper deals with the influence of radiation on natural convection airflows in confined areas. The investigated configuration is a square differentially-heated cavity at Ra = 1.5 × 109. Two dimensional LES computations have been carried out using a specific subgrid model for the thermal diffusivity and taking into account gas and wall radiation. Radiation within the fluid (due to the presence of water vapor in humid air) is considered using the SLW model developed by Denison and Webb and the Discrete Ordinate Method (S8 quadrature). Comparisons are carried out for four cases (without radiation, wall radiation only, gas radiation only and combined gas and wall radiation) and compared in terms of velocity and temperature fields as well as turbulent quantities (kinetic energy, turbulence intensity). Global heat transfer is also investigated and a comparison is made between the different cases.