Title: A Splash of Red

Description: High-speed photograph of a 2-mm droplet of red dye impacting on a thin layer of milk reveals crown formation and secondary droplets with a splash of red.

A single droplet of red dye is released from a height above a substrate. The extremely fast sequence of events following the droplet impact strongly depends on the type of liquid, droplet size, impact velocity, and the substrate. For a substrate covered with a very thin layer of liquid the impact of a droplet results in an upward jet forming a crown – a crown splash. High-speed photography reveals crown formation with tips of entrained milk covering the rim of the coronet. The rim breaks up in a number of satellite droplets determined by the most unstable wavelength of the Rayleigh-Plateau instability.

The high-speed photograph is obtained using a very short flash illumination and a digital camera.

In the inkjet printing industry, better understanding of the formation of satellites following droplet impact can improve the printing quality.

Credits: Wim van Hoeve, Tim Segers, Hans Kroes, Detlef Lohse, Michel Versluis of the Physics of Fluids Group, University of Twente, The Netherlands

References:

Web Page: http://pof.tnw.utwente.nl/

Contributed By: Wim van Hoeve