Splash (fluid mechanics)

The disturbance is typically caused by a solid object suddenly hitting the surface, although splashes can occur in which moving liquid supplies the energy.

Splash also happens when a liquid droplet impacts on a liquid or a solid surface;[citation needed] in this case, a symmetric corona (resembling a coronet) is usually formed as shown in Harold Edgerton's famous milk splash photography, as milk is opaque.

In the image of a brick splashing into water, one can identify freely moving airborne water droplets, a phenomenon typical of high Reynolds number flows; the intricate non-spherical shapes of the droplets show that the Weber number is high.

[citation needed] Also seen are entrained air bubbles in the body of the water, and an expanding ring of disturbance propagating away from the impact site.

Physicist Lei Xu and coworkers at the University of Chicago discovered that the splash due to the impact of a small drop of ethanol onto a dry solid surface could be suppressed by reducing the pressure below a specific threshold.

A splash after half a brick hits the water; the image is about half a metre across.
A drop of water splashing onto a hard surface
A drop of water splashing onto a water surface, showing the formation of a back-jet
Slow motion video of a fruit falling into water.