The Stability of an Annulus of Liquid in a Tube

Abstract

An annulus of liquid on the walls of a tube is sometimes found to be unstable under the action of surface forces and to break up, spontaneously, into a series of bubbles. This process is a possible mechanism for the transition from annular to slug flow. The wavelength of the breakup is predictable from potential-flow theory and the essential correctness of the prediction shown from experiment. It is shown that for liquid volume fractions less than about 6 percent no breakup occurs. The time to breakup is not found to be predictable.