Stirring by periodic arrays of microswimmers
(2017) In Journal of Fluid Mechanics 811. p.487-498- Abstract
The interaction between swimming micro-organisms or artificial self-propelled colloids and passive (tracer) particles in a fluid leads to enhanced diffusion of the tracers. This enhancement has attracted strong interest, as it could lead to new strategies to tackle the difficult problem of mixing on a microfluidic scale. Most of the theoretical work on this topic has focused on hydrodynamic interactions between the tracers and swimmers in a bulk fluid. However, in simulations, periodic boundary conditions (PBCs) are often imposed on the sample and the fluid. Here, we theoretically analyse the effect of PBCs on the hydrodynamic interactions between tracer particles and microswimmers. We formulate an Ewald sum for the leading-order... (More)
The interaction between swimming micro-organisms or artificial self-propelled colloids and passive (tracer) particles in a fluid leads to enhanced diffusion of the tracers. This enhancement has attracted strong interest, as it could lead to new strategies to tackle the difficult problem of mixing on a microfluidic scale. Most of the theoretical work on this topic has focused on hydrodynamic interactions between the tracers and swimmers in a bulk fluid. However, in simulations, periodic boundary conditions (PBCs) are often imposed on the sample and the fluid. Here, we theoretically analyse the effect of PBCs on the hydrodynamic interactions between tracer particles and microswimmers. We formulate an Ewald sum for the leading-order stresslet singularity produced by a swimmer to probe the effect of PBCs on tracer trajectories. We find that introducing periodicity into the system has a surprisingly significant effect, even for relatively small swimmer–tracer separations. We also find that the bulk limit is only reached for very large system sizes, which are challenging to simulate with most hydrodynamic solvers.
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- author
- de Graaf, Joost and Stenhammar, Joakim LU
- organization
- publishing date
- 2017
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- computational methods, micro-organism dynamics, Navier–Stokes equations
- in
- Journal of Fluid Mechanics
- volume
- 811
- pages
- 12 pages
- publisher
- Cambridge University Press
- external identifiers
-
- wos:000390352200024
- scopus:85027917816
- ISSN
- 0022-1120
- DOI
- 10.1017/jfm.2016.797
- language
- English
- LU publication?
- yes
- id
- 796c9e57-2dc7-41b0-b1a7-bb9d453d79ea
- date added to LUP
- 2016-12-23 08:03:15
- date last changed
- 2024-01-04 19:41:06
@article{796c9e57-2dc7-41b0-b1a7-bb9d453d79ea,
abstract = {{<p>The interaction between swimming micro-organisms or artificial self-propelled colloids and passive (tracer) particles in a fluid leads to enhanced diffusion of the tracers. This enhancement has attracted strong interest, as it could lead to new strategies to tackle the difficult problem of mixing on a microfluidic scale. Most of the theoretical work on this topic has focused on hydrodynamic interactions between the tracers and swimmers in a bulk fluid. However, in simulations, periodic boundary conditions (PBCs) are often imposed on the sample and the fluid. Here, we theoretically analyse the effect of PBCs on the hydrodynamic interactions between tracer particles and microswimmers. We formulate an Ewald sum for the leading-order stresslet singularity produced by a swimmer to probe the effect of PBCs on tracer trajectories. We find that introducing periodicity into the system has a surprisingly significant effect, even for relatively small swimmer–tracer separations. We also find that the bulk limit is only reached for very large system sizes, which are challenging to simulate with most hydrodynamic solvers.</p>}},
author = {{de Graaf, Joost and Stenhammar, Joakim}},
issn = {{0022-1120}},
keywords = {{computational methods; micro-organism dynamics; Navier–Stokes equations}},
language = {{eng}},
pages = {{487--498}},
publisher = {{Cambridge University Press}},
series = {{Journal of Fluid Mechanics}},
title = {{Stirring by periodic arrays of microswimmers}},
url = {{https://lup.lub.lu.se/search/files/27801173/Manuscript.pdf}},
doi = {{10.1017/jfm.2016.797}},
volume = {{811}},
year = {{2017}},
}