Hydrodynamic efficiency limit on a Marangoni surfer

Fuente: arXiv
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Autori principali: Daddi-Moussa-Ider, Abdallah, Golestanian, Ramin, Vilfan, Andrej
Natura: Preprint
Pubblicazione: 2023
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author Daddi-Moussa-Ider, Abdallah
Golestanian, Ramin
Vilfan, Andrej
author_facet Daddi-Moussa-Ider, Abdallah
Golestanian, Ramin
Vilfan, Andrej
contents A Marangoni surfer is an object embedded in a gas-liquid interface, propelled by gradients in surface tension. We derive an analytical theorem for the lower bound on the viscous dissipation by a Marangoni surfer in the limit of small Reynolds and capillary numbers. The minimum dissipation can be expressed with the reciprocal difference between drag coefficients of two passive bodies of the same shape as the Marangoni surfer, one in a force-free interface and the other in an interface with surface incompressibility. The distribution of surface tension that gives the optimal propulsion is given by the surface tension of the solution for the incompressible surface and the flow is a superposition of both solutions. For a surfer taking the form of a thin circular disk, the minimum dissipation is $16μa V^2$, giving a Lighthill efficiency of $1/3$. This places the Marangoni surfers among the hydrodynamically most efficient microswimmers.
format Preprint
id arxiv_https___arxiv_org_abs_2311_03878
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Hydrodynamic efficiency limit on a Marangoni surfer
Daddi-Moussa-Ider, Abdallah
Golestanian, Ramin
Vilfan, Andrej
Fluid Dynamics
Soft Condensed Matter
35Q30, 74F10, 76D07, 76D45, 76D55, 76Z10
A Marangoni surfer is an object embedded in a gas-liquid interface, propelled by gradients in surface tension. We derive an analytical theorem for the lower bound on the viscous dissipation by a Marangoni surfer in the limit of small Reynolds and capillary numbers. The minimum dissipation can be expressed with the reciprocal difference between drag coefficients of two passive bodies of the same shape as the Marangoni surfer, one in a force-free interface and the other in an interface with surface incompressibility. The distribution of surface tension that gives the optimal propulsion is given by the surface tension of the solution for the incompressible surface and the flow is a superposition of both solutions. For a surfer taking the form of a thin circular disk, the minimum dissipation is $16μa V^2$, giving a Lighthill efficiency of $1/3$. This places the Marangoni surfers among the hydrodynamically most efficient microswimmers.
title Hydrodynamic efficiency limit on a Marangoni surfer
topic Fluid Dynamics
Soft Condensed Matter
35Q30, 74F10, 76D07, 76D45, 76D55, 76Z10
url https://arxiv.org/abs/2311.03878