Bounds on the Spreading Radius in Droplet Impact: The Viscous Case

Fuente: arXiv
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Main Authors: Náraigh, Lennon Ó, Bustamante, Miguel D.
Format: Preprint
Published: 2024
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author Náraigh, Lennon Ó
Bustamante, Miguel D.
author_facet Náraigh, Lennon Ó
Bustamante, Miguel D.
contents We consider the problem of droplet impact and droplet spreading on a smooth surface in the case of a viscous Newtonian fluid. We revisit the concept of the rim-lamella model, in which the droplet spreading is described by a system of ordinary differential equations (ODEs). We show that these models contain a singularity which needs to be regularized to produce smooth solutions, and we explore the different regularization techniques in detail. We adopt one particular technique for further investigation, and we use differential inequalities to derive upper and lower bounds for the maximum spreading radius $\mathcal{R}_{max}$. Without having to resort to dimensional analysis or scaling arguments, our bounds confirm the leading-order behaviour $\mathcal{R}_{max} \sim \mathrm{Re}^{1/5}$, as well as a correction to the leading-order behaviour involving the combination $\mathrm{We}^{-1/2}\mathrm{Re}^{2/5}$, in agreement with the experimental literature on droplet spread. Our bounds are also consistent with full numerical solutions of the ODEs, as well as with energy-budget calculations, once head loss is accounted for in the latter.
format Preprint
id arxiv_https___arxiv_org_abs_2410_07904
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Bounds on the Spreading Radius in Droplet Impact: The Viscous Case
Náraigh, Lennon Ó
Bustamante, Miguel D.
Fluid Dynamics
We consider the problem of droplet impact and droplet spreading on a smooth surface in the case of a viscous Newtonian fluid. We revisit the concept of the rim-lamella model, in which the droplet spreading is described by a system of ordinary differential equations (ODEs). We show that these models contain a singularity which needs to be regularized to produce smooth solutions, and we explore the different regularization techniques in detail. We adopt one particular technique for further investigation, and we use differential inequalities to derive upper and lower bounds for the maximum spreading radius $\mathcal{R}_{max}$. Without having to resort to dimensional analysis or scaling arguments, our bounds confirm the leading-order behaviour $\mathcal{R}_{max} \sim \mathrm{Re}^{1/5}$, as well as a correction to the leading-order behaviour involving the combination $\mathrm{We}^{-1/2}\mathrm{Re}^{2/5}$, in agreement with the experimental literature on droplet spread. Our bounds are also consistent with full numerical solutions of the ODEs, as well as with energy-budget calculations, once head loss is accounted for in the latter.
title Bounds on the Spreading Radius in Droplet Impact: The Viscous Case
topic Fluid Dynamics
url https://arxiv.org/abs/2410.07904