抄録
Currently, the progress of eutrophication in various closed waters such as a reservoir is causing the outbreak of algae there. As a method to mitigate this problem, is the introduction of a jet pump type flow device. This device can cause the jet of mixed water of the upper water and lower water by sending the upper water to the pipe that was placed in the lower layer. However, the flows characteristics such as suction or entrainment change by the shape of the device. Therefore, in this study we used a model of a jet pump type flow device, experimentally examined the relationship between device shape and flow characteristics. In addition, we developed the theoretical formula. Finally, we judged the device shape quantitatively by comparing a theory value with measurements. The results were as follows: (1) By a theoretical formula, straight pipe is better for suction. (2) In order to mix enough the length of the tube must be at least 5 times the diameter.
