TRANSITION TO TIME-PERIODICITY OF A NATURAL-CONVECTION FLOW IN A 3D DIFFERENTIALLY HEATED CAVITY

The steady and time-periodic flow of air in a differentially heated cu bical cavity has been studied numerically, using the finite-volume met hod. In the steady flow regime, the scaling in the boundary layer alon g the wall has been investigated. In the periodic flow regime, the cal culated frequency was almost the same as for the two-dimensional squar e cavity, suggesting that the same instability mechanism is in both ca ses responsible for the bifurcation. There was, however, a strong thre e-dimensionality in the distribution of the amplitude of the oscillati ons.