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SUMMARY:Propulsion of active colloids in anisotropic fluids - Ziga Kos (Un
 iversity of Ljubljana)
DTSTART:20250822T084500Z
DTEND:20250822T093000Z
UID:TALK234772@talks.cam.ac.uk
DESCRIPTION:Active particles often swim in non-Newtonian and possibly even
  anisotropic fluids. We show how anisotropic orientational order can not o
 nly steer the swimming direction\, but also provide new propulsion modes o
 f microswimmers that are not able to move in isotropic fluids. Specificall
 y\, we derive the mobility tensor of passive spheres in nematic fluids tho
 ugh a non-equilibrium multipolar analysis of the director field\, effectiv
 ely finding a perturbative solution to the coupled nematodynamic equations
  for the director and the flow field. The mobility tensor links the swimmi
 ng velocity and the rotation rate with the forces and torques applied at g
 iven viscoelastic material parameters and equilibrium multipolar moments\,
  showing for example how continuous propulsion can be achieved by applying
  a torque on a rotationally symmetric colloidal particle. Beyond driven pa
 rticles\, we can expand the approach using a squirmer model for active mic
 roswimmers\, determining how swimming direction and speed can be tuned by 
 the nematic parameters. The result is a contribution towards developing th
 e rules for propulsion in complex fluids and tuning the mutual microswimme
 r interactions.\n[1] E. Caf\, Ž. Kos\, to be submitted.[2] T. Yao\, Ž. K
 os\, Q. X. Zhang\, Y. Luo\, E. B. Steager\, M. Ravnik\, K. J. Stebe\, Topo
 logical defect-propelled swimming of nematic colloids\, Science Advances 8
  (2022) eabn8176.[3] S.-J. Kim\, Ž. Kos\, E. Um\, J. Jeong\, Symmetricall
 y pulsating bubbles swim in an anisotropic fluid by nematodynamics\, Natur
 e communications 15 (2024) 1220.
LOCATION:Seminar Room 1\, Newton Institute
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