Abstract
This paper describes the interfacial phenomena generated on the gas-liquid interface. Details of the collision, rebound, and coalescence of small water droplets at the clean air-water interface were studied experimentally and theoretically. The behavior of the falling liquid drop in the air-water interface was observed with the high speed video camera system. It was found that the water drop at lower impact velocities floats on the air-water interface. When a larger water drop coalesces with water, the surface flow generated by the coalescence ejects the secondary smaller droplet of water. The maximum depth by the drop collision is described by the Froude number and the Weber number. The behavior of the coalescence wave on the water column and the satellite droplet produced by the break up of the water column was also revealed experimentally.