Abstract
This paper describes the water entry phenomena created by the impact of solid-liquid compound projectile. The spherical NdFeB permanent magnet was used as solid, and kerosene-based magnetic fluid was used as liquid in the experiment. The cavity of air in water was observed with high-speed video camera system. The effect of magnetic fluid adsorbed to the spherical magnet was clarified. The impact of the magnetic fluid coated sphere on the free surface of water readily causes the formation of subsurface cavity. The effect of the alternating magnetic fields on the cavity was also revealed.
