THE RELATION BETWEEN THE INTERFACIAL SHEAR-STRESS AND THE WAVE MOTION IN A STRATIFIED FLOW

A model is developed to describe the interfacial shear stress at a wavy interface with wave characteristics. Experiments have been conducted with near-horizontal (4.1-degrees) and near-vertical (87-degrees) flat plates for air-water concurrent stratified flows. The interfacial shear stress and normal and flow directional interface velocities were measured. Assuming a simple relation between the gas velocity near the interface and film thickness, the turbulent shear stress due to the wave motion is expressed by the normal interfacial velocity and the relative gas velocity. The model developed agrees well with the experimental data for a wide range of horizontal and vertical stratified flow.