AIR ENTRAINMENT IN THE DEVELOPING FLOW REGION OF PLUNGING JETS .2. EXPERIMENTAL

When a waterjet impinges a pool of water as rest, air bubbles may be e ntrained and carried away below the pool free surface this process is called plunging jet entrainment. The study presents new experimental d ata obtained with a vertical supported jet, Distributions of air conce ntration and mean air-water velocity, and bubble chord length distribu tions measured in the developing shear layer are presented, The result s indicate that the distributions of void fraction follow closely anal ytical solution of the diffusion equation. Further, the momentum shear layer and the air bubble diffusion layer do not coincide. Chord lengt h data show a wide range of air bubble sizes and overall the experimen tal results suggest strong interactions between the entrained air bubb les and the momentum transfer mechanisms.