BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Collective Microswimmer Motility in Complex Environments - Fabian 
 Schwarzendahl (Max-Planck-Institute for Dynamics and Self-Organization)
DTSTART:20190528T130000Z
DTEND:20190528T140000Z
UID:TALK125398@talks.cam.ac.uk
CONTACT:Anne Herrmann
DESCRIPTION:The behavior of microswimmers is strongly influenced by the in
 teraction with their environments which can be other microorganisms or con
 fining walls.\nI will first report on the swimming behavior of the green a
 lga Chlamydomonas reinhardtii in confinement where we find an increased pr
 obability of the cell swimming close to the confining wall. We discovered 
 that the near-wall swimming probability scales with the local wall curvatu
 re. The model that we propose\, consisting of an asymmetric dumbbell\, des
 cribes the near-wall swimming accurately and does not require any fitting 
 parameter. In fact\, we found that the important ingredient to the curvatu
 re guided navigation is the torque stemming from the asymmetry of the orga
 nism.\n\nSecondly\, I will report on the influence of hydrodynamic interac
 tions between microswimmers. We introduce a novel model for biological mic
 roswimmers that creates the flow field of the corresponding microswimmers\
 , and takes into account the shape anisotropy of the swimmer's body and st
 roke-averaged flagella. By employing multiparticle collision dynamics\, we
  directly couple the swimmer's dynamics to the fluid's. We characterize th
 e nonequilibrium phase dia- gram\, as the filling fraction and Péclet nu
 mber are varied\, and find density heterogeneities in the distribution of 
 both pullers and pushers\, due to hydrodynamic instabilities. We find a ma
 ximum degree of clustering at intermediate filling fractions and at large 
 Péclet numbers resulting from a competition of hydrodynamic and steric i
 nteractions between the swimmers. We develop an analytical theory that sup
 ports these results. This maximum might represent an optimum for the micro
 organisms' colonization of their environment.\n\n
LOCATION:MR11\, Centre for Mathematical Sciences\, Wilberforce Road\, Camb
 ridge
END:VEVENT
END:VCALENDAR