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Speaker:  (Lund ľ�ϸ���Ӱ��)

Title: Collective (hydro)dynamics of microswimmer suspensions in and out of confinement

Abstract: Due to their non-equilibrium character, the collective dynamics of active matter systems is often dictated by long-ranged hydrodynamic interactions. One example is the collective motion of swimming, rear-actuated (“pusher”) bacteria that interact through their long-ranged dipolar flow-fields to create a state of so-called “active turbulence” with collective swimming over long distances. This behavior is in contrast to the behaviour of rear-actuated (“puller”) organisms, that do not exhibit any collective motion in 3 dimensions. In this talk, I will present results from large-scale, particle resolved lattice Boltzmann simulations of >106 model microswimmers in both unbounded, 3 dimensional systems, and confined, quasi-2D systems. The results will give new information about the well-known transition to active turbulence in 3 dimensions, and reveal a distinctly different behaviour of confined microswimmers, showing that the details of the experimental geometry are crucial in determining collective phenomena in active matter.