Sykes, Thomas C;
Cimpeanu, Radu;
Fudge, Ben D;
Castrejon Pita, Jose;
Castrejon-Pita, Alfonso A;
(2023)
Droplet impact dynamics on shallow pools.
Journal of Fluid Mechanics
, 970
, Article A34. 10.1017/jfm.2023.622.
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Abstract
When a fast droplet impacts a pool of the same fluid, a thin ejecta sheet that dominates the early-time dynamics emerges within the first few microseconds. Fluid and impact properties are known to affect its evolution; we experimentally reveal that the pool depth is a critical factor too. Whilst ejecta sheets can remain separate and subsequently fold inwards on deeper pools, they instead develop into outward-propagating lamellae on sufficiently shallow pools, undergoing a transition that we delineate by comprehensively varying impact inertia and pool depth. Aided by matching direct numerical simulation results, we find that this transition stems from a confinement effect of the pool base on the impact-induced pressure, which stretches the ejecta sheet to restrict flow into it from the droplet on sufficiently shallow pools. This insight is also applied to elucidate the well-known transition due to Reynolds number.
| Type: | Article |
|---|---|
| Title: | Droplet impact dynamics on shallow pools |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1017/jfm.2023.622 |
| Publisher version: | https://doi.org/10.1017/jfm.2023.622 |
| Language: | English |
| Additional information: | This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited. |
| Keywords: | breakup/coalescence, thin films |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10174134 |
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