INTERACTION BETWEEN TURBULENCE AND A SWARM OF BUBBLES IN SIMPLE CONFIGURATIONS

The present paper is devoted to the study of the turbulence in the liquid phase of a vertical cocurrent air-water bubbly flow. The configuration has been chosen to be as simple as possible, in order to bring out some basic mechanisms of the interaction between the air bubbles and the turbulence in the liquid phase. The influence of the presence of air bubbles on the various standard local parameters characterizing turbulence-namely, the turbulent intensity, the Reynolds stress tensor, the onedimensional spectrum, and the time correlation of the longitudinal fluctuating velocity-has been examined. As a starting point for a possible modeling of the turbulence in the liquid phase, an estimation of the fluctuating kinetic energy, based on both analytical and dimensional arguments, is proposed.