Water entry of a magnetic fluid coated sphere

This paper describes the dynamics of the air cavity created by water entry of magnet-magnetic fluid projectile. The impact of a projectile, permanent magnet coated with kerosene-based magnetic fluid, on the free surface of water is investigated experimentally. The cavity of air in water created by the impact of the projectile is observed with the high-speed video camera system. Effects of the adsorption of magnetic fluid and alternating magnetic fields are revealed.

Research Highlights
► Magnetic fluid adsorption to a spherical magnet causes the formation of cavity in the water entry.
► Applied alternating magnetic field leads to the complicated cavity interface and earlier pinch-off.
► Sinking velocity of the projectile in water depends on the frequency of alternating magnetic field.