EVIDENCE OF WEAK CHAOS WITHIN PLUG-SLUG TRANSITION IN HORIZONTAL TWO PHASE FLOW

Intermittent behaviour has been observed in gas-liquid flows in a horizontal pipe and a weak sign of deterministic chaos has been diagnosed within a transition from plug to slug flow. The analysis has been performed on the basis of an algorithm which exploits the concept of short-term predictability of chaotic motions. The method is completely non-parametric and works whatever the distribution function of the data points may be. The weak sign of chaos is in contrast with the Lorenz-type systems (strong chaos) and supports the idea of Kolmogorov about irregular motion in hydrodynamical systems.