Abstract
We introduce a solvable Lagrangian model for droplet bouncing. The model predicts that, for an axisymmetric drop, the contact time decreases to a constant value with increasing Weber number, in qualitative agreement with experiments, because the system is well approximated as a simple harmonic oscillator. We introduce asymmetries in the velocity, initial droplet shape, and contact line drag acting on the droplet and show that asymmetry can often lead to a reduced contact time and lift-off in an elongated shape. The model allows us to explain the mechanisms behind non-axisymmetric bouncing in terms of surface tension forces. Once the drop has an elliptical footprint the surface tension force acting on the longer sides is greater. Therefore the shorter axis retracts faster and, due to the incompressibility constraints, pumps fluid along the more extended droplet axis. This leads to a positive feedback, allowing the drop to jump in an elongated configuration, and more quickly.
| Original language | English |
|---|---|
| Pages (from-to) | 985-994 |
| Number of pages | 10 |
| Journal | Soft Matter |
| Volume | 13 |
| Issue number | 5 |
| Early online date | 5 Jan 2017 |
| DOIs | |
| Publication status | Published - 7 Feb 2017 |
Bibliographical note
© 2016,The Royal Society of Chemistry. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.Keywords
- wetting, drop dynamics, non-linear science, chaos
