From splashing to bouncing: the influence of viscosity on the impact of suspension droplets on a solid surface

Abstract

We experimentally investigated the splashing of dense suspension droplets impacting a solid surface, extending prior work to the regime where the viscosity of the suspending liquid becomes a significant parameter. The overall behavior can be described by a combination of two trends. The first one is that the splashing becomes favored when the kinetic energy of individual particles at the surface of a droplet overcomes the confinement produced by surface tension. This is expressed by a particle-based Weber number $W{e}_p$. The second is that splashing is suppressed by increasing the viscosity of the solvent. This is expressed by the Stokes number $St$, which influences the effective coefficient of restitution of colliding particles. We developed a phase diagram where the splashing onset is delineated as a function of both $W{e}_p$ and $St$. A surprising result occurs at very small Stokes number, where not only splashing is suppressed but also plastic deformation of the droplet. This leads to a situation where droplets can bounce back after impact, an observation we are able to reproduce using discrete particle numerical simulations that take into account viscous interaction between particles and elastic energy.

References in corpus (13)

• Drop Splashing on a Dry Smooth Surface
• Drop impact upon micro- and nanostructured superhydrophobic surfaces
• Ultrafast Interference Imaging of Air in Splashing Dynamics
• Creation of prompt and thin-sheet splashing by varying surface roughness or increasing air pressure
• Coefficient of restitution for wet particles
• Thin Film Formation During Splashing of Viscous Liquids
• How micropatterns and air pressure affect splashing on surfaces
• Drop impact experiments of non-Newtonian liquids on micro-structured surfaces
• Stokes' Cradle: Normal Three-Body Collisions between Wetted Particles
• Splashing onset in dense suspension droplets
• Dense Suspension Splat: Monolayer Spreading and Hole Formation After Impact
• Still water: dead zones and collimated ejecta from the impact of granular jets
• Microscopic dissipation in a cohesionless granular jet impact

Cited by in corpus (4)

• Wet granular flow control through liquid induced cohesion
• Growth of Aggregates with Liquid-Like Ice-Shells in Protoplanetary Discs
• Transient flows and migration in granular suspensions: key role of Reynolds-like dilatancy
• Drop Impact Dynamics of Complex Fluids: A Review