Experimental analysis of basic phenomena regarding gas entrainment of liquid surface

In the gas-entraining phenomena at gas-liquid interface, it is often difficult to exactly grasp the similarity because gravity, viscous force, surface tension and so on take part simultaneously in the inertial force of flow, and there are sometimes problems in the conversion and application of the evaluation by model test to actual machines. Based on the results of the research on the gas-entraining phenomena by vortices, for the purpose of obtaining the knowledge that contributes to the establishment of the method of evaluating actual machines by model test, the relation of surface waves which are the basic external disturbance of free surfaces to gas entrainment was experimentally investigated, and extremely noteworthy phenomena were discovered. The experimental setup and the experimental method are explained. As the experimental results, the experimental conditions, the swirling flow characteristics of vortices, the change in the frequency of bubble generation by wave height, the change in gas-entraining mode by wave height, the effect that waves exerted to vortex core structure, and the relation of the change in the period of waves to the frequency of gas entrainment are reported. (K.I.)