A study on the temperature variation of rise velocity for large clean bubbles

A series of microphysical laboratory experiments studying the hydrodynamics of single bubbles were conducted to measure the variation of rise velocity , V-B, with temperature, T, and radius r. Bubbles with an equivalent spheri cal radius between 377 and 4500 mum were studied for T varying between 0 de grees and 40 degreesC. While for nonoscillating bubbles V-B increases with T; due to the significance of oscillations, V-B decreases with T for oscill ating bubbles, in conjunction with an increase in trajectory oscillations w ith T. Using observations from this study and data from other researchers, a three-part parameterization of V-B(r, T) is proposed with transitions at Re = 1 and the onset of oscillations, where Re is the Reynolds number The T for the transition to oscillatory behavior was found to vary linearly with r. An empirical parameterization of V-B(r, T) for oscillatory and nonoscil latory bubbles that correctly incorporates the effect of T is presented.