Both side walls are adiabatic and the box is heated from below with a bottom wall temperature of 301K and a top wall temperature of 299K.The fluid is considered an ideal gas with appropriate reference properties assigned. All convergence factors comply more than satisfactorily. Even the heat flux values differ by only one one-hundredth of a Watt. Again, as it is for case1, a pair of dominant vortices are formed within the rectangular region. However, unlike case1 the direction of air flow in the vortices is reversed.
Hot air rises in the central region and cool air drops along the side walls.
In addition, two eddies appear in the lower corners. While comparing results of case1 with case2, it is interesting to note that although the Rayleigh number has increased by at least a magnitude of one hundred that the velocities have little more than doubled. This suggests a power relationship between maximum velocities and the Rayleigh number.