水中から水面に向けて打ち上げられた固体球の運動と気液界面の挙動

抄録

To investigate the variation in a sphere's motion and the behavior of the air-water interface induced by the sphere, a solid sphere is launched vertically upward in water toward the air-water interface. Four spheres with different densities ρ_p were studied: a stainless steel sphere (ρ_p = 7930 kg/m³), an alumina sphere (ρ_p = 3900 kg/m³), a Teflon sphere (ρ_p = 2180 kg/m³), and a Duracon sphere (ρ_p = 1360 kg/m³). By experimentally visualizing the sphere motion in water, their launch velocity can be set with high accuracy. When a sphere passes through the air--water interface, it makes the interface more complex and entrains water. Additionally, spheres with a small value of ρ_p were demonstrated to not always vertically collide with the air--water interface.