DETECTION AND ANALYSIS OF TRANSITION FROM ANNULAR TO INTERMITTENT FLOW IN VERTICAL TUBES

In vertical co-current gas-liquid flow, the transition from annular to intermittent flow occurs when gas core becomes interrupted by liquid bridges due to the instability of the interfacial capillary waves. An analytical model is formulated to explain the liquid bridging in terms of the growth of finite amplitude interfacial capillary waves. Experi mental results show that the longest wave length, which is associated with the transition, is about eight times the wave length of waves mov ing with the velocity of the liquid film.