TY - JOUR TI - Effect of radiation on the flow structure and heat transfer in a 2-D gray medium AU - Rachedi Nesrine AU - Bouafia Madiha AU - Guellal Messaoud AU - Hamimid Saber JN - Thermal Science PY - 2019 VL - 23 IS - 6 SP - 3603 EP - 3614 PT - Article AB - A numerical study of combined natural convection and radiation in a square cavity filled with a gray non-scattering semi-transparent fluid is conducted. The horizontal walls are adiabatic and the vertical are differentially heated. Convection is treated by the finite volumes approach and the discrete ordinates method is used to solve radiative transfer equation using S6 order of angular quadrature. Representative results illustrating the effects of the Rayleigh number, the optical thickness and the Planck number on the flow and temperature distribution are reported. In addition, the results in terms of the average Nusselt number obtained for various parametric conditions show that radiation modifies significantly the thermal behavior of the fluid within the enclosure.