When does an impacting drop stop bouncing?

Abstract

Non-wetting substrates allow impacting liquid drops to spread, recoil, and takeoff, provided they are not too heavy (Biance et al. 2006) or too viscous (Jha et al. 2020). In this article, using direct numerical simulations with the volume of fluid method, we investigate how viscous stresses and gravity conspire against capillarity to inhibit drop rebound. Close to the bouncing to non-bouncing transition, we evidence that the initial spreading stage can be decoupled from the later retraction and takeoff, allowing to understand the rebound as a process converting the surface energy of the spread liquid into kinetic energy. Drawing an analogy with coalescence induced jumping, we propose a criterion for the transition from the bouncing to the non-bouncing regime, namely by the condition $O{h}_c+B{o}_c\sim 1$, where $O{h}_c$ and $B{o}_c$ are the Ohnesorge number and Bond number at the transition, respectively. This criterion is in excellent agreement with the numerical results. We also elucidate the mechanisms of bouncing inhibition in the heavy and viscous drops limiting regimes by calculating the energy budgets and relating them to the drop's shape and internal flow.

Supplemental videos are available here: https://youtube.com/playlist?list=PLf5C5HCrvhLHG5t3iPscUuEp_gbD4XHyU

References in corpus (5)

• Drop Splashing on a Dry Smooth Surface
• Impact forces of water drops falling on superhydrophobic surfaces
• When does an impacting drop stop bouncing?
• Universal aspects of droplet spreading dynamics in Newtonian and non-Newtonian Fluids
• Drop impact on viscous liquid films

Cited by in corpus (9)

• Unifying theory of scaling in drop impact: Forces & maximum spreading diameter
• When does an impacting drop stop bouncing?
• Drop impact on viscous liquid films
• The role of viscosity on drop impact forces on non-wetting surfaces
• Drop rebound at low Weber number
• To jump or not to jump: Adhesion and viscous dissipation dictate the detachment of coalescing wall-attached bubbles
• Droplet rebounds off a fluid bath at low Weber numbers
• Impacting spheres: from liquid drops to elastic beads
• Drops can Perpetually Bounce over a Vibrating Wettable Solid