Void drift is one of the main flow interactions between subchannels. It results from the tendency of a two-phase flow to approach an equilibrium condition without a transverse pressure differential. In this paper, void drift is phenomenologically described. Experiments were performed for two-phase flow of air and water mixtures through a multiple channel consisting of two interconnected subchannels. Data on the developing flow redistributions of both phases are presented. The "void settling model" proposed by Lahey et al. is also studied by use of the present data.
