Numerical study of natural convection dominated heat transfer in a ventilated cavity: Case of forced flow playing simultaneous assisting and opposing roles

Mixed convection heat transfer in a ventilated cavity is numerically studied by solving the mixed convection equations with the Boussinesq approximation. Results are presented in terms of streamlines, isotherms and heat transfer for different combinations of the governing parameters namely, the Reynolds number (10 ⩽ Re ⩽ 5000), the Rayleigh number (104 ⩽ Ra ⩽ 106) and the relative height of the openings (B = h′/H′ = 1/4). The numerical results show the presence of a maximum interaction between the effects of the forced and natural convection and the existence of different flow regimes. The latter are delineated in the Ra–Re plane and the values of Re separating the different regions are determined and correlated versus Ra.