Rayleigh-bénard Convection: Onset Of Natural Convection And Transition From Laminar-oscillatory Convection Flow

A numerical study of Rayleigh-Bénard convection in a rectangular cavity has been presented. The onset of natural convection and the transition to oscillatory convection were considered in this study. The finite volume method was used to solve numerically the governing equations of the phenomenon. The pressure-velocity coupling was matched by SIMPLER Algorithm of Patankar. The study concerned has been made for the Rayleigh number varied from 103 to 106 in order to define the Rac1 corresponding to the onset of convection for the different aspect ratio of the cavity. The transition threshold regime laminar-Oscillatory convection which is defined by Rac-2 is determined and discussed. In addition a discussion of the different modes of bifurcation of convection were also determined and discussed.