The present work is an attempt to address this problem, by analyzing the flow of an isolated liquid plug which is in direct contact with the capillary tube wall. FIG 1: Two configurations of gas–liquid flow in a capillary tube: (a) wet-plug flow re-gime and (b) dry-plug flow regime.olume 3, Issue 2-4, 2012Thermal Transport Behavior of a Liquid Plug Moving inside a Dry Capillary Tube 113 The radial location by Thulasidas et al. (1997) is given only for developed ve-locity profile in wet-plug flow which in this case is for L/D = 2 and 4.