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Main Authors: Biswas, Shiba, Burada, P. S., Sekhar, G. P. Raja
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2411.12252
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author Biswas, Shiba
Burada, P. S.
Sekhar, G. P. Raja
author_facet Biswas, Shiba
Burada, P. S.
Sekhar, G. P. Raja
contents We investigate the low Reynolds number hydrodynamics of a spherical swimmer with a predominantly hydrophobic surface, except for a hydrophilic active patch. This active patch covers a portion of the surface and exhibits chiral activity that varies as a function of $θ$ and $ϕ$. Our study considers two types of active patches: (i) a symmetric active patch (independent of $ϕ$) and (ii) an arbitrary active patch (depends on both $θ$ and $ϕ$). The swimming velocity, rotation rate, and flow field of the swimmer are calculated analytically. The objective of this work is to find the optimal configurations for both patch models to maximize the swimmer's velocity and efficiency. Interestingly, the maximum velocity can be controlled by adjusting the hydrophobicity, patch configuration, and strength of the surface activity. We find that for the symmetric patch model, the swimmer's velocity is $U_{SP} = 1.414 U_s$, where $U_s$ is the velocity of a swimmer whose surface is fully covered with chiral activity as a reference. For the arbitrary patch model, the velocity is $U_{AP} = 1.45 U_s$, which is higher than that of the symmetric patch model. Our results indicate that swimmers with low hydrophobicity exhibit efficient swimming characteristics. Additionally, due to the incomplete coverage of the active patch, the Stokeslet and Rotlet terms appear in the flow field generated by the swimmer, which is a deviation compared to the case of a swimmer whose surface is fully covered with chiral activity. This study provides insights useful for designing synthetic active particles, which can be applied, for example, in targeted drug delivery, chemotaxis, and phototaxis.
format Preprint
id arxiv_https___arxiv_org_abs_2411_12252
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Chiral swimmer with a regular arbitrary active patch
Biswas, Shiba
Burada, P. S.
Sekhar, G. P. Raja
Fluid Dynamics
We investigate the low Reynolds number hydrodynamics of a spherical swimmer with a predominantly hydrophobic surface, except for a hydrophilic active patch. This active patch covers a portion of the surface and exhibits chiral activity that varies as a function of $θ$ and $ϕ$. Our study considers two types of active patches: (i) a symmetric active patch (independent of $ϕ$) and (ii) an arbitrary active patch (depends on both $θ$ and $ϕ$). The swimming velocity, rotation rate, and flow field of the swimmer are calculated analytically. The objective of this work is to find the optimal configurations for both patch models to maximize the swimmer's velocity and efficiency. Interestingly, the maximum velocity can be controlled by adjusting the hydrophobicity, patch configuration, and strength of the surface activity. We find that for the symmetric patch model, the swimmer's velocity is $U_{SP} = 1.414 U_s$, where $U_s$ is the velocity of a swimmer whose surface is fully covered with chiral activity as a reference. For the arbitrary patch model, the velocity is $U_{AP} = 1.45 U_s$, which is higher than that of the symmetric patch model. Our results indicate that swimmers with low hydrophobicity exhibit efficient swimming characteristics. Additionally, due to the incomplete coverage of the active patch, the Stokeslet and Rotlet terms appear in the flow field generated by the swimmer, which is a deviation compared to the case of a swimmer whose surface is fully covered with chiral activity. This study provides insights useful for designing synthetic active particles, which can be applied, for example, in targeted drug delivery, chemotaxis, and phototaxis.
title Chiral swimmer with a regular arbitrary active patch
topic Fluid Dynamics
url https://arxiv.org/abs/2411.12252