Berlin 2018 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 54: Statistical Physics of Biological Systems I (joint session BP/DY)
DY 54.6: Vortrag
Donnerstag, 15. März 2018, 10:45–11:00, H 2013
A Spheroidal Squirmer in Shear Flow — •Kai Qi1, Elmar Westphal2, Gerhard Gompper1, and Roland G. Winkler1 — 1Theoretical Soft Matter and Biophysics, Institute for Advanced Sim- ulation and Institute of Complex Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany — 2Jülich Centre for Neutron Science, Forschungszentrum Jülich, D-52425 Jülich, Germany
Squirmers are generic models for microswimmers like bacteria and algae. The behavior of a spheroidal squirmer [1, 2] in shear flow is studied by hydrodynamic simulations via the multiparticle collision dynamics [3] approach. Due to the elongated shapes of spheroids, alignment along the shear direction is observed for both passive spheroidal colloids and squirmers in the weak shear flow. When the shear rate exceeds a critical value, alignment changes from the shear to the vorticity direction. The alignment transition reveals a clear dependence on the hydrodynamic dipole of the swimmer’s flow field. Pullers with a large positive force-dipole coefficient exhibit gradual variations of the alignment direction, whereas abrupt changes are found for pushers with a large negative coefficient. Comparison between elongated and spherical squirmers reveals a significant shape dependence of their behaviors in shear flow.
[1] M. Theers, E. Westphal, G. Gompper, and R. G. Winkler, Soft Matter 12, 7372 (2016).
[2] J. Elgeti, R. G. Winkler, and G. Gompper, Rep. Prog. Phys. 78, 056601 (2015).
[3] G. Gompper, T. Ihle, D. M. Kroll, and R. G. Winkler, Adv. Polym. Sci. 221, 1 (2009).