Scaling law for a buckled elastic filament in a shear flow

Fuente: arXiv
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Main Authors: Sznajder, Pawel, Zdybel, Piotr, Liu, Lujia, Ekiel-Jezewska, Maria L.
Format: Preprint
Published: 2023
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author Sznajder, Pawel
Zdybel, Piotr
Liu, Lujia
Ekiel-Jezewska, Maria L.
author_facet Sznajder, Pawel
Zdybel, Piotr
Liu, Lujia
Ekiel-Jezewska, Maria L.
contents We analyze the three-dimensional buckling of an elastic filament in a shear flow of a viscous fluid at low Reynolds number and high Peclet number. We apply the Euler-Bernoulli beam (elastica) theoretical model. We show the universal character of the full 3D spectral problem for the small perturbation of the thin filament from a straight position of arbitrary orientation. We use the eigenvalues and eigenfunctions for the linearized elastica equation in the shear plane, found earlier by [Liu et al., 2024] with the Chebyshev spectral collocation method, to solve the full 3D eigenproblem. We provide a simple analytic approximation to the eigenfunctions, represented as Gaussian wavepackets. As the main result of the paper, we derive square-root dependence of the eigenfunction wavenumber on the parameter $\tildeχ=-η\sin 2ϕ\sin^2θ$, where $η$ is the elastoviscous number, and the filament orientation is determined by the zenith angle $θ$ with respect to the vorticity direction and the azimuthal angle $ϕ$ relative to the flow direction. We also compare the eigenfunctions with shapes of slightly buckled elastic filaments with a non-negligible thickness with the same Young's modulus, using the bead model and performing numerical simulations with the precise Hydromultipole numerical codes.
format Preprint
id arxiv_https___arxiv_org_abs_2307_07215
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Scaling law for a buckled elastic filament in a shear flow
Sznajder, Pawel
Zdybel, Piotr
Liu, Lujia
Ekiel-Jezewska, Maria L.
Fluid Dynamics
Soft Condensed Matter
We analyze the three-dimensional buckling of an elastic filament in a shear flow of a viscous fluid at low Reynolds number and high Peclet number. We apply the Euler-Bernoulli beam (elastica) theoretical model. We show the universal character of the full 3D spectral problem for the small perturbation of the thin filament from a straight position of arbitrary orientation. We use the eigenvalues and eigenfunctions for the linearized elastica equation in the shear plane, found earlier by [Liu et al., 2024] with the Chebyshev spectral collocation method, to solve the full 3D eigenproblem. We provide a simple analytic approximation to the eigenfunctions, represented as Gaussian wavepackets. As the main result of the paper, we derive square-root dependence of the eigenfunction wavenumber on the parameter $\tildeχ=-η\sin 2ϕ\sin^2θ$, where $η$ is the elastoviscous number, and the filament orientation is determined by the zenith angle $θ$ with respect to the vorticity direction and the azimuthal angle $ϕ$ relative to the flow direction. We also compare the eigenfunctions with shapes of slightly buckled elastic filaments with a non-negligible thickness with the same Young's modulus, using the bead model and performing numerical simulations with the precise Hydromultipole numerical codes.
title Scaling law for a buckled elastic filament in a shear flow
topic Fluid Dynamics
Soft Condensed Matter
url https://arxiv.org/abs/2307.07215