There is also a lack of agreement as to what constitutes churn flow. It is fairly certainly a gas continuous flow. There is growing agreement that there are huge waves present and some of the liquid is carried as drops. Sekoguchi and Mori (1997) and Sawai et al. (2004) using measurements from their multiple probes (92 over an axial length of 2.325 m) obtained time/axial position/void fraction information. From this they were able to identify huge wave from amongst disturbance waves and slugs. They classified individual structures as huge waves from their size together with the fact that their velocities depended significantly on the corresponding axial length. This was in contrast to disturbance waves where the velocity of individual waves only increased slightly with the axial extent of these waves. They also found that the frequency of huge waves first increased and then decrease with increasing gas superficial velocity. Similarly, their velocities were found to deviate from the line for slug flow velocities and pass through a maximum and then a minimum.
