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Lattice-Boltzmann simulations of microswimmer-tracer interactions

de Graaf, Joost and Stenhammar, Joakim LU (2017) In Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 95(2).
Abstract

Hydrodynamic interactions in systems composed of self-propelled particles, such as swimming microorganisms and passive tracers, have a significant impact on the tracer dynamics compared to the equivalent "dry" sample. However, such interactions are often difficult to take into account in simulations due to their computational cost. Here, we perform a systematic investigation of swimmer-tracer interaction using an efficient force-counterforce-based lattice-Boltzmann (LB) algorithm [De Graaf et al., J. Chem. Phys. 144, 134106 (2016)JCPSA60021-960610.1063/1.4944962] in order to validate its ability to capture the relevant low-Reynolds-number physics. We show that the LB algorithm reproduces far-field theoretical results well, both in a... (More)

Hydrodynamic interactions in systems composed of self-propelled particles, such as swimming microorganisms and passive tracers, have a significant impact on the tracer dynamics compared to the equivalent "dry" sample. However, such interactions are often difficult to take into account in simulations due to their computational cost. Here, we perform a systematic investigation of swimmer-tracer interaction using an efficient force-counterforce-based lattice-Boltzmann (LB) algorithm [De Graaf et al., J. Chem. Phys. 144, 134106 (2016)JCPSA60021-960610.1063/1.4944962] in order to validate its ability to capture the relevant low-Reynolds-number physics. We show that the LB algorithm reproduces far-field theoretical results well, both in a system with periodic boundary conditions and in a spherical cavity with no-slip walls, for which we derive expressions here. The force-lattice coupling of the LB algorithm leads to a "smearing out" of the flow field, which strongly perturbs the tracer trajectories at close swimmer-tracer separations, and we analyze how this effect can be accurately captured using a simple renormalized hydrodynamic theory. Finally, we show that care must be taken when using LB algorithms to simulate systems of self-propelled particles, since its finite momentum transport time can lead to significant deviations from theoretical predictions based on Stokes flow. These insights should prove relevant to the future study of large-scale microswimmer suspensions using these methods.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics
volume
95
issue
2
publisher
American Physical Society
external identifiers
  • scopus:85013849017
  • wos:000400013700009
ISSN
1539-3755
DOI
10.1103/PhysRevE.95.023302
language
English
LU publication?
yes
id
5a808f0a-3a45-41a4-aec6-dbee51544dcc
date added to LUP
2017-03-08 11:12:00
date last changed
2018-01-07 11:54:28
@article{5a808f0a-3a45-41a4-aec6-dbee51544dcc,
  abstract     = {<p>Hydrodynamic interactions in systems composed of self-propelled particles, such as swimming microorganisms and passive tracers, have a significant impact on the tracer dynamics compared to the equivalent "dry" sample. However, such interactions are often difficult to take into account in simulations due to their computational cost. Here, we perform a systematic investigation of swimmer-tracer interaction using an efficient force-counterforce-based lattice-Boltzmann (LB) algorithm [De Graaf et al., J. Chem. Phys. 144, 134106 (2016)JCPSA60021-960610.1063/1.4944962] in order to validate its ability to capture the relevant low-Reynolds-number physics. We show that the LB algorithm reproduces far-field theoretical results well, both in a system with periodic boundary conditions and in a spherical cavity with no-slip walls, for which we derive expressions here. The force-lattice coupling of the LB algorithm leads to a "smearing out" of the flow field, which strongly perturbs the tracer trajectories at close swimmer-tracer separations, and we analyze how this effect can be accurately captured using a simple renormalized hydrodynamic theory. Finally, we show that care must be taken when using LB algorithms to simulate systems of self-propelled particles, since its finite momentum transport time can lead to significant deviations from theoretical predictions based on Stokes flow. These insights should prove relevant to the future study of large-scale microswimmer suspensions using these methods.</p>},
  articleno    = {023302},
  author       = {de Graaf, Joost and Stenhammar, Joakim},
  issn         = {1539-3755},
  language     = {eng},
  month        = {02},
  number       = {2},
  publisher    = {American Physical Society},
  series       = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics},
  title        = {Lattice-Boltzmann simulations of microswimmer-tracer interactions},
  url          = {http://dx.doi.org/10.1103/PhysRevE.95.023302},
  volume       = {95},
  year         = {2017},
}