Dynamic Behavior of Water Jet Accompanied with Air Suction

In order to atomize a liquid, the authors have investigated the behavior of air- water jets. In a series of experiments, we have discovered a strange phenomenon that the water jet accompanied with an air suction from the free surface has made a periodic radial splash of water drop. The purpose of the present paper is to clear out the origin of this phenomenon by flow visualization. The dynamic behavior of this phenomenon has been photographed by a digital camera aided with a flash light and high-speed video camera. Those experiments enable us to find the origin of such phenomena due to a formation of a single air bubble at the flow separation region inside the nozzle and due to explosive expansion of the bubble after injected in the free space.