Run-and-tumble particles with hydrodynamics: sedimentation, trapping, and upstream swimming.
We simulate by lattice Boltzmann the nonequilibrium steady states of run-and-tumble particles (inspired by a minimal model of bacteria), interacting by far-field hydrodynamics, subject to confinement. Under gravity, hydrodynamic interactions barely perturb the steady state found without them, but for particles in a harmonic trap such a state is quite changed if the run length is larger than the confinement length: a self-assembled pump is formed. Particles likewise confined in a narrow channel show a generic upstream flux in Poiseuille flow: chiral swimming is not required.
Nash
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RW
SUPA, School of Physics, University of Edinburgh, JCMB Kings Buildings, Edinburgh EH9 3JZ, United Kingdom.
Adhikari
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R
Tailleur
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J
Cates
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ME
D001419:Bacteria / Q000166:cytology*; D018407:Bacterial Physiological Phenomena; D006112:Gravitation; D057446:Hydrodynamics; D008954:Models, Biological; D013550:Swimming