LIQUID TURBULENCE STRUCTURE AT A SHEARED AND WAVY GAS-LIQUID INTERFACE

Interfacial momentum transfer was studied in cocurrent and countercurr ent wavy-stratified flows in a rectangular channel using both the hot- wire anemometry (HWA) and the non-intrusive photochromic dye activatio n (PDA) techniques. In cocurrent and countercurrent stratified flows w ith a wavy interface, the interfacial shear and waves were found to ch ange the kinematic and turbulence structures of the liquid phase signi ficantly. In particular, the mean streamwise velocity profile became n early constant in the upper half of the liquid phase, and the magnitud e of the turbulent streamwise and Vertical fluctuations correlated wit h the interfacial shear and the wave amplitude, respectively. Numerica l predictions of the experimental data were obtained with the k-epsilo n model of turbulence. New interface conditions were proposed for wavy flows which yielded predictions in good agreement with the experiment al data for both cocurrent and countercurrent flows. (C) 1997 Elsevier Science Ltd.