Simulations of splashing micro-scale droplets on a dry surface

Speaker Name: 
Arnout Boelens
Speaker Organization: 
Stanford University
Start Time: 
Monday, April 24, 2017 - 4:00pm
End Time: 
Monday, April 24, 2017 - 5:00pm
Engineering 2, Room 280
Daniele Venturi


Emerging printing applications require control of the impact of ink droplets on surfaces at increasingly small length scales. At atmospheric pressure and at sufficiently large velocities, a familiar splash is produced when a droplet impacts a solid dry surface. However, counterintuitively, when the ambient pressure is reduced, the droplet smoothly deposits on the surface. Due to a limited knowledge of contact-line behavior and liquid-sheet stability, the origins of this so-called ''pressure effect'' are not well understood.In this presentation the pressure effect is explored numerically by resolving the Navier-Stokes equations down to a 3-nm resolution. The simulations reproduce key experimental features and, importantly, provide new insights into length and time scales that are not easily accessible by experiments. This has allowed us to identify a previously unknown high-speed "rolling'' contact line regime. In addition, our scaling analysis suggests that there is universal physics across different splashing regimes.