Underwater acrobatics of vibrating cylinders

The physics behind water-diving projectiles are traditionally investigated in the context of impactor shape, entry speed, and surface texture. Such studies often neglect impulses experienced by projectiles during descent into the fluid. In this experimental study, we systematically investigate splash and cavity behavior arising from the water entry of free-falling, vibrating hydrophilic and hydrophobic cylinders across various drop heights. Pulsating cylinders experience changes to splash crowns, cavity shape and pinch-off, and hydrodynamic drag when compared to their non-pulsating counterparts. These observations augur well for understanding water entry applications where vibrations are unmitigable.