The effect of a vertical lapse rate of temperature on the spiral flow of a fluid in a heated rotating cylinder

Experiments have been performed with a viscous fluid contained in a rotating cylinder heated from below. Previous theoretical explanations of the flow patterns obtained in these experiments assumed that the convective terms in the heat transfer equation were negligible. The present paper gives a treatment which includes one of these convective terms. The results confirm the physical reasoning that, when the laps rate is positive, the stability is increased and that the motion is therefore decreased.