A REFUTATION OF KING'S RULE FOR MULTI-DIMENSIONAL EXTERNAL NATURAL CONVECTION.

EXPERIMENTS ARE CARRIED OUT TO TEST THE VALIDITY OF KING'S RULE FOR EVALUATING A CHARACTERISTIC LENGTH FOR PROBLEMS OF MULTI-DIMENSIONAL EXTERNAL NATURAL CONVECTION AS WELL AS THE LIENHARD RULE. A HEATED VERTICAL CYLINDER OF EQUAL HEIGHT AND DIAMETER WAS USED, WITH HEAT BEING TRANSFERRED FROM TOP, SIDE, AND BOTTOM. THE USE OF KING'S RULE LED TO 40-50% OVERPREDICTIONS. ALTHOUGH LIENHARD'S RULE YIELDED PREDICTIONS THAT WERE SOMEWHAT CLOSER TO THE DATA THE LEVEL OF AGREEMENT DOES NOT APPEAR TO WARRANT ITS ADOPTION.