Water entry with disrupted splash closure

When a body impacts the water surface it typically opens a gas-filled cavity.  At sufficiently high Weber number, the cavity seals when the above-surface splash domes over on itself.  This behavior is characteristic of the surface seal cavity closure regime.  Mansoor et al. [1] showed that by inhibiting splash closure, one can induce a deep seal closure normally seen at lower impact speeds.  However, as speed is increased it is unclear if inhibiting the splash closure will continue to result in deep seal, revert back to surface seal, or result in an entirely different cavity closure mechanism.  Here we investigate the mechanisms of cavity closure when the splash sheet is disrupted at moderate to high impact speed (O(10-100 m/s)).  Over a large velocity range, we show that the cavity closure mechanism varies and evidently affects the resulting volume and gas composition of the cavity.

 

[1] Mansoor, Mohammad M., et al. "Water entry without surface seal: extended cavity formation." Journal of Fluid Mechanics 743 (2014): 295-326.