Inertial effects on the interphase drag force and rheology of dilute suspensions of buoyant droplets at low Reynolds number

Fuente: arXiv
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Autori principali: Fintzi, Nicolas, Pierson, Jean-Lou
Natura: Preprint
Pubblicazione: 2026
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author Fintzi, Nicolas
Pierson, Jean-Lou
author_facet Fintzi, Nicolas
Pierson, Jean-Lou
contents In this work, we compute the hydrodynamic force and the first and second moments of force acting on a translating spherical droplet immersed in a uniform flow using the reciprocal theorem. We consider the low but finite Reynolds number regime, $Re = a U ρ_f / μ_f$, and the dilute limit of small droplet volume fraction $ϕ$. Here, $U$ denotes the magnitude of the relative velocity between the phases, $a$ the droplet radius, and $ρ_f$ and $μ_f$ the density and viscosity of the continuous phase, respectively. We show that the $O(Re)$ inertial corrections to the first and second moments of force scale as $O(ρ_f ϕU^2)$ and $O(aρ_fϕU^2)$, respectively. Moreover, the ensemble average of the drag force and the higher-order force moments over the distribution of droplet velocities introduces additional contributions proportional to the velocity variance of the dispersed phase, both in the interphase momentum exchange and in the effective stress of the continuous phase. As a consequence, in dilute emulsions of buoyant droplets, the effective stress depends quadratically on the relative velocity between the phases, on the velocity variance of the dispersed phase, and on the spatial gradients of these quantities.
format Preprint
id arxiv_https___arxiv_org_abs_2601_19377
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Inertial effects on the interphase drag force and rheology of dilute suspensions of buoyant droplets at low Reynolds number
Fintzi, Nicolas
Pierson, Jean-Lou
Fluid Dynamics
In this work, we compute the hydrodynamic force and the first and second moments of force acting on a translating spherical droplet immersed in a uniform flow using the reciprocal theorem. We consider the low but finite Reynolds number regime, $Re = a U ρ_f / μ_f$, and the dilute limit of small droplet volume fraction $ϕ$. Here, $U$ denotes the magnitude of the relative velocity between the phases, $a$ the droplet radius, and $ρ_f$ and $μ_f$ the density and viscosity of the continuous phase, respectively. We show that the $O(Re)$ inertial corrections to the first and second moments of force scale as $O(ρ_f ϕU^2)$ and $O(aρ_fϕU^2)$, respectively. Moreover, the ensemble average of the drag force and the higher-order force moments over the distribution of droplet velocities introduces additional contributions proportional to the velocity variance of the dispersed phase, both in the interphase momentum exchange and in the effective stress of the continuous phase. As a consequence, in dilute emulsions of buoyant droplets, the effective stress depends quadratically on the relative velocity between the phases, on the velocity variance of the dispersed phase, and on the spatial gradients of these quantities.
title Inertial effects on the interphase drag force and rheology of dilute suspensions of buoyant droplets at low Reynolds number
topic Fluid Dynamics
url https://arxiv.org/abs/2601.19377