Radial local heat flow distributions at CF for different Grashof numbers Gr, 106: (a) (1) 0.0062; (2) 0.041; (3) 0.068; (4) 0.149; (5) 0.269; (6) 0.313; (b): (1) 0.813; (2) 1.645; (3) 3.174; (4) 5.175; (5) 7.259; (c): (1) 0.558; (2) 3.173.