Swimming efficiency in viscosity gradients

Fuente: arXiv
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Auteurs principaux: Gong, Jiahao, Shaik, Vaseem A., Elfring, Gwynn J.
Format: Preprint
Publié: 2024
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author Gong, Jiahao
Shaik, Vaseem A.
Elfring, Gwynn J.
author_facet Gong, Jiahao
Shaik, Vaseem A.
Elfring, Gwynn J.
contents In this note, we study the effect of viscosity gradients on the energy dissipated by the motion of microswimmers and the associated efficiency of that motion. Using spheroidal squirmer model swimmers in weak linearly varying viscosity fields, we find that efficiency depends on whether they generate propulsion from the back (pushers) or the front (pullers). Pushers are faster and more efficient when moving down gradients but slower and less efficient moving up viscosity gradients, and the opposite is true for pullers. However, both pushers and pullers display negative viscotaxis, therefore pushers dynamically tend to the most efficient orientation while pullers the least. We also evaluate the effect of shape on power expenditure and efficiency when swimming in viscosity gradients and find that in general the change in both due to gradients monotonically decreases with increasing slenderness. This work shows how shape and gait play an important role in determining dynamics and efficiency in inhomogeneous environments, and demonstrating that both efficiency minimizing and maximizing stable dynamical states are possible.
format Preprint
id arxiv_https___arxiv_org_abs_2405_02432
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Swimming efficiency in viscosity gradients
Gong, Jiahao
Shaik, Vaseem A.
Elfring, Gwynn J.
Fluid Dynamics
Soft Condensed Matter
In this note, we study the effect of viscosity gradients on the energy dissipated by the motion of microswimmers and the associated efficiency of that motion. Using spheroidal squirmer model swimmers in weak linearly varying viscosity fields, we find that efficiency depends on whether they generate propulsion from the back (pushers) or the front (pullers). Pushers are faster and more efficient when moving down gradients but slower and less efficient moving up viscosity gradients, and the opposite is true for pullers. However, both pushers and pullers display negative viscotaxis, therefore pushers dynamically tend to the most efficient orientation while pullers the least. We also evaluate the effect of shape on power expenditure and efficiency when swimming in viscosity gradients and find that in general the change in both due to gradients monotonically decreases with increasing slenderness. This work shows how shape and gait play an important role in determining dynamics and efficiency in inhomogeneous environments, and demonstrating that both efficiency minimizing and maximizing stable dynamical states are possible.
title Swimming efficiency in viscosity gradients
topic Fluid Dynamics
Soft Condensed Matter
url https://arxiv.org/abs/2405.02432