BEHAVIOR OF SINGLE AIR BUBBLES HELD STATIONARY IN DOWNWARD FLOWS

Abstract

The behavior of single air bubbles was studied by holding them stationary by downward flows. Two series of experiments, involving undisturbed flow and disturbed flow by an immersed cylinder, respectively, were conducted in the Reynolds number range 2000-5000 and at the equivalent spherical diameter of bubble 0.4-2 cm. In the disturbed flow, the intensity of turbulence was 0.13 and the integral scale was of the same order of magnitude as bubble diameter. And although the bubble shape was changed considerably from time to time by the effect of turbulence, the relative velocity of bubbles was almost the same as in the undisturbed flow. The averaged ratio of the wake region volume to the bubble volume for the two cases was 4.7.