Shape of isolated bubble in intermittent flows in horizontal straight tube

An experimental study of the shape of a single bubble similar to those observed in horizontal plug/slug flow was performed by visual observation and conductance probes in this paper. The results show that the shape of the nose and body of bubble depends on the Froude number defined by gas/liquid mixture velocity, whereas the shape of the back region of bubble depends on both the Froude number and bubble length. The photographic pictures show that the motion of bubble is related to the characteristics of bubble head and the transition from plug flow to slug flow occurs when the back of the bubble changes from staircase to hydraulic jump pattern with increasing the Froude number and bubble length.