Energy transition in air of a sphere launched vertically upward in water

In a present experiment, a solid sphere with a density of 2.64 × 103 kg/m3 and diameter of 25.4 mm was launched vertically upward in water toward the air–water interface. The submergence depth was changed and the launch velocity was adjusted so that the Reynolds number of the sphere immediately after passing the air–water interface was almost equal at each submergence depth. The effects of the submergence depth on the motion of the sphere and behavior of the air–water interface were investigated, which indicated that the Reynolds number immediately after the sphere passed through the air–water interface was Re¯w1∼3000 at all submergence depths (1.0d≤H≤6.0d; d is the diameter of the sphere and H is the submergence depth). The experimental values of the maximum displacement position were always smaller than the theoretical values owing to the energy dispersion caused by the water droplets entrained around the sphere. When the submergence depth was H∕d