Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-22T18:46:41.704Z Has data issue: false hasContentIssue false

Stirring by periodic arrays of microswimmers

Published online by Cambridge University Press:  13 December 2016

Joost de Graaf*
Affiliation:
Department of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
Joakim Stenhammar
Affiliation:
Division of Physical Chemistry, Lund University, P.O. Box 124, S-221 00 Lund, Sweden
*
Email address for correspondence: [email protected]

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 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.

Type
Papers
Copyright
© 2016 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Beenakker, C. W. J. 1986 Ewald sum of the Rotne–Prager tensor. J. Chem. Phys. 85, 15811582.CrossRefGoogle Scholar
Darwin, C. 1953 Note on hydrodynamics. Math. Proc. Camb. 49, 342354.CrossRefGoogle Scholar
Drescher, K., Dunkel, J., Cisneros, L. H., Ganguly, S. & Goldstein, R. E. 2011 Fluid dynamics and noise in bacterial cell–cell and cell–surface scattering. Proc. Natl Acad. Sci. USA 108, 1094010945.CrossRefGoogle ScholarPubMed
Drescher, K., Goldstein, R. E., Michel, N., Polin, M. & Tuval, I. 2010 Direct measurement of the flow field around swimming microorganisms. Phys. Rev. Lett. 105, 168101.CrossRefGoogle ScholarPubMed
Dunkel, J., Putz, V. B., Zaid, I. M. & Yeomans, J. M. 2010 Swimmer–tracer scattering at low Reynolds number. Soft Matt. 6, 42684276.CrossRefGoogle Scholar
Evans, A. A., Ishikawa, T., Yamaguchi, T. & Lauga, E. 2011 Orientational order in concentrated suspensions of spherical microswimmers. Phys. Fluids 23, 111702.CrossRefGoogle Scholar
Ewald, P. P. 1921 Die Berechnung optischer und elektrostatischer Gitterpotentiale. Ann. Phys. 369 (3), 253287.CrossRefGoogle Scholar
de Graaf, J., Menke, H., Mathijssen, A. J. T. M., Fabritius, M., Holm, C. & Shendruk, T. N. 2016 Lattice-Boltzmann hydrodynamics of anisotropic active matter. J. Chem. Phys. 144 (13), 134106.Google ScholarPubMed
Hünenberger, P. H. & McCammon, J. A. 1999 Ewald artifacts in computer simulations of ionic solvation and ion–ion interaction: a continuum electrostatics study. J. Chem. Phys. 110, 18561872.CrossRefGoogle Scholar
Ishikawa, T., Locsei, J. T. & Pedley, T. J. 2010 Fluid particle diffusion in a semidilute suspension of model micro-organisms. Phys. Rev. E 82, 021408.Google Scholar
Jeanneret, R., Pushkin, D. O., Kantsler, V. & Polin, M. 2016 Entrainment dominates the interaction of microalgae with micron-sized objects. Nat. Commun. 7, 12518.CrossRefGoogle ScholarPubMed
Jepson, A., Martinez, V. A., Schwarz-Linek, J., Morozov, A. & Poon, W. C. K. 2013 Enhanced diffusion of nonswimmers in a three-dimensional bath of motile bacteria. Phys. Rev. E 88, 041002.Google Scholar
af Klinteberg, L. & Tornberg, A.-K. 2014 Fast Ewald summation for Stokesian particle suspensions. Intl J. Numer. Meth. Fluids 76, 669698.CrossRefGoogle Scholar
Krishnamurthy, D. & Subramanian, G. 2015 Collective motion in a suspension of micro-swimmers that run-and-tumble and rotary diffuse. J. Fluid Mech. 781, 422466.CrossRefGoogle Scholar
Leptos, K. C., Guasto, J. S., Gollub, J. P., Pesci, A. I. & Goldstein, R. E. 2009 Dynamics of enhanced tracer diffusion in suspensions of swimming eukaryotic microorganisms. Phys. Rev. Lett. 103, 198103.CrossRefGoogle ScholarPubMed
Lin, Z., Thiffeault, J.-L. & Childress, S. 2011 Stirring by squirmers. J. Fluid Mech. 669, 167177.CrossRefGoogle Scholar
Lugli, F., Brini, E. & Zerbetto, F. 2012 Shape governs the motion of chemically propelled Janus swimmers. J. Phys. Chem. C 116, 592598.CrossRefGoogle Scholar
Marchetti, M. C., Joanny, J.-F., Ramaswamy, S., Liverpool, T. B., Prost, J., Rao, M. & Simha, R. A. 2013 Hydrodynamics of soft active matter. Rev. Mod. Phys. 85, 11431189.CrossRefGoogle Scholar
Mino, G. L., Dunstan, J., Rousselet, A., Clement, E. & Soto, R. 2013 Induced diffusion of tracers in a bacterial suspension: theory and experiments. J. Fluid Mech. 729, 423444.CrossRefGoogle Scholar
Morozov, A. & Marenduzzo, D. 2014 Enhanced diffusion of tracer particles in dilute bacterial suspensions. Soft Matt. 10, 27482758.CrossRefGoogle ScholarPubMed
Nash, R. W., Adhikari, R. & Cates, M. E. 2008 Singular forces and pointlike colloids in lattice Boltzmann hydrodynamics. Phys. Rev. E 77, 026709.Google ScholarPubMed
Pozrikidis, C. 1996 Computation of periodic Green’s functions of Stokes flow. J. Engng Maths 30, 7996.CrossRefGoogle Scholar
Pushkin, D. O., Shum, H. & Yeomans, J. 2013 Fluid transport by individual microswimmers. J. Fluid Mech. 726, 525.CrossRefGoogle Scholar
Pushkin, D. O. & Yeomans, J. M. 2013 Fluid mixing by curved trajectories of microswimmers. Phys. Rev. Lett. 111, 188101.CrossRefGoogle ScholarPubMed
Stenhammar, J., Karlström, G. & Linse, P. 2011 Structural anisotropy in polar fluids subjected to periodic boundary conditions. J. Chem. Theor. Comput. 726, 41654174.CrossRefGoogle Scholar
Thiffeault, J.-L. 2015 Distribution of particle displacements due to swimming microorganisms. Phys. Rev. E 92, 023023.Google ScholarPubMed
Thiffeault, J.-L. & Childress, S. 2010 Stirring by swimming bodies. Phys. Lett. A 374, 34873490.CrossRefGoogle Scholar
Underhill, P. T., Hernandez-Ortiz, J. P. & Graham, M. D. 2008 Diffusion and spatial correlations in suspensions of swimming particles. Phys. Rev. Lett. 100, 248101.CrossRefGoogle ScholarPubMed
Valeriani, C., Li, M., Novosel, J., Arlt, J. & Marenduzzo, D. 2011 Colloids in a bacterial bath: simulations and experiments. Soft Matt. 7, 52285238.CrossRefGoogle Scholar
Wells, B. A. & Chaffee, A. L. 2015 Ewald summation for molecular simulations. J. Chem. Theor. Comput. 11, 36843695.CrossRefGoogle ScholarPubMed
Wu, X.-L. & Libchaber, A. 2000 Particle diffusion in a quasi-two-dimensional bacterial bath. Phys. Rev. Lett. 84, 30173020.CrossRefGoogle Scholar