Drift velocity of elongated bubbles in inclined pipes

Abstract

The drift velocity, which is defined as the velocity of long bubbles propagating into a stagnant liquid column, has been treated successfully in the past using inviscid flow theory. However, different approaches were used for the horizontal and the vertical cases. In this work, Benjamin's simple approach, which was originally applied for the horizontal case only, is extended to the inclined and the vertical cases, taking into consideration surface tension effects. Good agreement with experimental data is obtained.