Synopsis: Suppressing the Splash

A drop’s splash can be reduced and even eliminated by varying the softness of the surface that it hits.
Synopsis figure
C. Howland et al., Phys. Rev. Lett (2016)

When a droplet impacts a hard surface, it splashes, ejecting liquid fragments in every direction. This is fine if the fluid needs to be distributed over a wide area, but isn’t so great in hospitals that need to stay sterile, or in applications involving toxic fluids. Now researchers have shown that a drop’s splash is suppressed if the surface is made of a soft material, like a gel or a rubber.

Robert Style, from the University of Oxford, UK, and colleagues bombarded a series of soft silicone gels of varying stiffness with drops of ethanol and compared their splashing behavior to that of drops impacting a hard surface. During the initial impact, the drops behave in the same way for all surfaces: The drop flattens and starts spreading out like a pancake. For hard surfaces, this outer, thinner rim of fluid then breaks up into a fine spray of tinier drops. For softer and softer surfaces, the spraying decreases until eventually the pancake stays whole. According to the group’s simulations, the deformation of the soft surface during the first 30 𝜇s of impact is what’s behind splash suppression. This deformation absorbs just a few percent of the drop’s kinetic energy, but can be sufficient to keep it intact.

The team found that splashes can be generated on soft surfaces, but the height from which the drops have to be released is nearly twice that required to get a splash on a hard surface.

This research is published in Physical Review Letters.

–Katherine Wright

Katherine Wright is a Contributing Editor for Physics.


Features

More Features »

Announcements

More Announcements »

Subject Areas

Fluid Dynamics

Previous Synopsis

Semiconductor Physics

Valley of the Dichalcogenides

Read More »

Next Synopsis

Particles and Fields

Making Monopoles with Waves

Read More »

Related Articles

Synopsis: Eyeing the Storm
Fluid Dynamics

Synopsis: Eyeing the Storm

Numerical simulations of a hurricane-like system have determined the conditions necessary for the formation of a calm “eye” in the center of the storm. Read More »

Synopsis: The Coldest Water
Fluid Dynamics

Synopsis: The Coldest Water

A new technique has measured the lowest temperature ever recorded for liquid water. Read More »

Focus: Liquid String Vibrations
Fluid Dynamics

Focus: Liquid String Vibrations

A liquid microchannel—the line where three soap films meet—vibrates like a string whose diameter shrinks as the shaking force increases.   Read More »

More Articles