Concerning the Characteristic of Bubble Mixed Flows : An Experiment of Bubble Flow through a Divergent Channel

Abstract

It has often been noticed that a water flow in which air bubbles are mixed shows a similarity to cavitation. Not only these photographic similarities, but the dynamic similarities as found in the following experiment were also noticed. When the flow velocities of cavitation bubbles in a pump impeller were measured by photographic method, the writer assumed the cavitating water flow to be a kind of compressible fluid mixed with vapour bubbles. The higher velocity of bubbles, the discontinuity in pressure distribution, and the generation of shock were explained, but the pressure could not be measured in the pump impeller. In this experiment the velocities of bubbles of cavitation which appeared in a divergent flow were measured by a camera which had been designed to photograph the locus of bubbles on a running film. The velocities of bubbles were not lowered in the divergent flow. Also, in measuring the pressure, a discontinuity in pressure distribution was noticed. By examining the dynamic similarity between cavitation and air mixed water flow, the characteristics of the vapor bubble flow were shown.