ESPCI web site
PMMH’s weekly seminar is held every Friday at 11 am (map)
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire PMMH - Sara Jabbari Farouji (Gutenberg University, Mainz, Germany)
Controlling stability and transport of magnetic microswimmers by an external field
Inspired by intriguing dynamics of magnetotactic bacteria, we present a minimal kinetic model for magnetic swimmers in an external magnetic field to investigate their collective behavior. Our kinetic model couples a Fokker-Planck equation for active particles in an external magnetic field to the Stokes flow.
Combining linear stability analysis and nonlinear 3D continuum simulations, we investigate the hydrodynamic stability and transport of magnetic swimmers as a function of activity and magnetic field strengths. We show that at sufficiently high activity and moderate magnetic field strengths, a homogeneous polar steady state is unstable and distinct types of splay and bend instabilities for puller and pusher swimmers emerge. Pushers form wave-like structures perpendicular to the field while pullers form wave-like lanes along the field. These instabilities arise from the amplification of anisotropic hydrodynamic interactions in the external alignment and lead to a partial depolarization and a reduction of the average transport speed of the swimmers in the field direction. Interestingly, at higher field strengths the homogeneous polar state becomes stable and a transport efficiency identical to that of active particles without hydrodynamic interactions is restored. We discuss our results in relation to the experimental findings.
The audience is composed of people with rather heterogeneous backgrounds including specialists in solids, fluids, granular flows, statistical physics... so the idea is to keep your talk understandable by people not necessarily working in your field... The seminar time slot runs from 11am to noon so the best is to make the talk last around 45 minutes to leave some time for discussion.
- Séminaires ESPCI-ENS de biophysique
- Séminaires du Département de Physique de l’ENS
- Séminaires du Laboratoire d’Hydrodynamique de l’X
- Séminaire de Mécanique d’Orsay (page web FAST)
- Séminaire de Mécanique d’Orsay (page web LIMSI)
- Séminaire de Mécanique des Fluides de l’Institut Jean le Rond d’Alembert
- Séminaires du laboratoire MSC, Paris VII
- Séminaires Gulliver
Link to cofee seminar (internal, every Thursday)
