Abstract:
In order to investigate the significance of cyclic interaction in the evolution of fluctuating convective flow in a rectangular cell of porous material, the behavior of confined and unconfined flows are compared. In the latter case the constant pressure boundary condition at the top surface does not force the fluid to recirculate around the cell. However, regular oscillatory flow similar to that which occurs in an enclosed cell is still observed. This indicates that the oscillatory flow arises from the instability of the thermal boundary layer on the heated bottom surface. In both cases the frequency of the oscillatory flow is proportional to the Rayleigh number to the power of 3/2.
