Turbulent stretching of dumbbells with hydrodynamic interactions: an analytical study

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Autori principali: Picardo, Jason R., Vincenzi, Dario
Natura: Preprint
Pubblicazione: 2025
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author Picardo, Jason R.
Vincenzi, Dario
author_facet Picardo, Jason R.
Vincenzi, Dario
contents We study the stretching of an elastic dumbbell in a turbulent flow, with the aim of understanding and quantifying the effect of hydrodynamic interactions (HI) between the beads of the dumbbell. Adopting the Batchelor-Kraichnan model for the flow, we derive a Fokker-Planck equation and solve it analytically to obtain the probability distribution of the dumbbell's extension. Using different formulations of the HI tensor, we find that HI preferentially enhances the stretching of stiff dumbbells, i.e., those with a small Weissenberg number. We also evaluate the averaging approximations commonly used to simplify the description of HI effects; the consistently-averaged approximation shows that HI result in a less-pronounced coil-stretch transition in chaotic flows. Finally, we confirm the relevance of our analytical results by a comparison with Brownian dynamics simulations of dumbbells transported in a direct numerical simulation of homogeneous isotropic turbulence.
format Preprint
id arxiv_https___arxiv_org_abs_2506_14282
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Turbulent stretching of dumbbells with hydrodynamic interactions: an analytical study
Picardo, Jason R.
Vincenzi, Dario
Fluid Dynamics
Soft Condensed Matter
Statistical Mechanics
We study the stretching of an elastic dumbbell in a turbulent flow, with the aim of understanding and quantifying the effect of hydrodynamic interactions (HI) between the beads of the dumbbell. Adopting the Batchelor-Kraichnan model for the flow, we derive a Fokker-Planck equation and solve it analytically to obtain the probability distribution of the dumbbell's extension. Using different formulations of the HI tensor, we find that HI preferentially enhances the stretching of stiff dumbbells, i.e., those with a small Weissenberg number. We also evaluate the averaging approximations commonly used to simplify the description of HI effects; the consistently-averaged approximation shows that HI result in a less-pronounced coil-stretch transition in chaotic flows. Finally, we confirm the relevance of our analytical results by a comparison with Brownian dynamics simulations of dumbbells transported in a direct numerical simulation of homogeneous isotropic turbulence.
title Turbulent stretching of dumbbells with hydrodynamic interactions: an analytical study
topic Fluid Dynamics
Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2506.14282