Journal Article

PreJuSER-10018

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Mesoscale Simulations of Hydrodynamic Squirmer Interactions

Götze, I.FZJ* ; Gompper, G.FZJ*

2010
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/9312  doi:10.1103/PhysRevE.82.041921

Abstract: The swimming behavior of self-propelled microorganisms is studied by particle-based mesoscale simulations. The simulation technique includes both hydrodynamics and thermal fluctuations that are both essential for the dynamics of microswimmers. The swimmers are modeled as squirmers, i.e., spherical objects with a prescribed tangential surface velocity, where the focus of thrust generation can be tuned from pushers to pullers. For passive squirmers (colloids), we show that the velocity autocorrelation function agrees quantitatively with the Boussinesq approximation. Single active squirmers show a persistent random-walk behavior, determined by forward motion, lateral diffusion, and orientational fluctuations, in agreement with theoretical predictions. For pairs of squirmers, which are initially swimming in parallel, we find an attraction for pushers and a repulsion for pullers, as expected. The hydrodynamic force between squirmer pairs is calculated as a function of the center-to-center distances d(cm) and is found to be consistent with a logarithmic distance dependence for d(cm) less than about two sphere diameters; here, the force is considerably stronger than expected from the far-field expansion. The dependence of the force strength on the asymmetry of the polar surface velocity is obtained. During the collision process, thermal fluctuations turn out to be very important and to strongly affect the postcollision velocity directions of both squirmers.

Keyword(s): J

Note: Record converted from VDB: 12.11.2012

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Contributing Institute(s):

1. Theorie der Weichen Materie und Biophysik (IFF-2)
2. Theorie der Weichen Materie und Biophysik (IAS-2)
3. Jülich Aachen Research Alliance - High-Performance Computing (JARA-HPC)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)

Appears in the scientific report 2010

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Database coverage:
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