In order to clarify the draft-tube performance of cross flow-turbines or the submerged water-jet-performance through the air, two-dimensional aerated-bubbly-flow-behavior within a narrow duct, especially on the energy recovery rate of the jet, have been systematically experimentally studied, when the jet is vertically injected into cahm water. The recovery rate η is closely related to the jet velocity V and the volume rate μaw of air-water-mixture. Such a flow pattern is also visualized.
