Fast droplet impact onto slowly moving deep pools

Fuente: arXiv
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Bibliographic Details
Main Authors: Sykes, Thomas C., Alventosa, Luke F. L., Castrejon-Pita, J. Rafael, Cimpeanu, Radu, Harris, Daniel M., Castrejon-Pita, Alfonso A.
Format: Preprint
Published: 2025
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author Sykes, Thomas C.
Alventosa, Luke F. L.
Castrejon-Pita, J. Rafael
Cimpeanu, Radu
Harris, Daniel M.
Castrejon-Pita, Alfonso A.
author_facet Sykes, Thomas C.
Alventosa, Luke F. L.
Castrejon-Pita, J. Rafael
Cimpeanu, Radu
Harris, Daniel M.
Castrejon-Pita, Alfonso A.
contents When a fast droplet impacts a pool, the resulting ejecta sheet dynamics determine the final impact outcome. At low Capillary numbers, the ejecta sheet remains separate from a deep static pool, whilst at higher viscosities it develops into a lamella. Here, we show that the common natural scenario of a slowly moving deep pool can change the upstream impact outcome, creating highly three-dimensional dynamics no longer characterised by a single descriptor. By considering how pool movement constrains the evolution of the ejecta sheet angle, we reach a length-scale invariant parameterisation for the upstream transition that holds for a wide range of fluids and impact conditions. Direct numerical simulations show similar dynamics for an equivalent oblique impact, indicating that the pool boundary layer does not play a decisive role for low pool-droplet speed ratios. Our results also provide insight into the physical mechanism that underpins pool impact outcomes more generally.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03682
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fast droplet impact onto slowly moving deep pools
Sykes, Thomas C.
Alventosa, Luke F. L.
Castrejon-Pita, J. Rafael
Cimpeanu, Radu
Harris, Daniel M.
Castrejon-Pita, Alfonso A.
Fluid Dynamics
When a fast droplet impacts a pool, the resulting ejecta sheet dynamics determine the final impact outcome. At low Capillary numbers, the ejecta sheet remains separate from a deep static pool, whilst at higher viscosities it develops into a lamella. Here, we show that the common natural scenario of a slowly moving deep pool can change the upstream impact outcome, creating highly three-dimensional dynamics no longer characterised by a single descriptor. By considering how pool movement constrains the evolution of the ejecta sheet angle, we reach a length-scale invariant parameterisation for the upstream transition that holds for a wide range of fluids and impact conditions. Direct numerical simulations show similar dynamics for an equivalent oblique impact, indicating that the pool boundary layer does not play a decisive role for low pool-droplet speed ratios. Our results also provide insight into the physical mechanism that underpins pool impact outcomes more generally.
title Fast droplet impact onto slowly moving deep pools
topic Fluid Dynamics
url https://arxiv.org/abs/2511.03682