Onset of Natural Convection and Transition Laminar-Oscillatory Convection Flow in Rayleigh-Bénard Configuration

A numerical study of Rayleigh-B nard convection in a rectangular cavity has been presented. The onset of natural convection and the transition from laminar to oscillatory convection were considered in this study. The finite volume method was used to solve numerically the governing equations of the phenomenon and the pressure-velocity coupling was matched by SIMPLER Algorithm of Patankar. This study was carried out for Rayleigh number varied from 10 3 to 10 6 in order to control the first value of critical Rayleigh number, Rac-1 corresponding the onset of convection, and that for different aspect ratios of the cavity. The threshold transition regime of laminar-oscillatory convection is depicted by the second critical Rayleigh number Rac-2. Also, the different modes of bifurcation of convection were determined and discussed.