Fluctuations and collective behaviour in microswimmer suspensions

by Joakim Stenhammar (Lund University)

Tuesday 31 Jan 2017, 13:30 → 14:30 Europe/Stockholm

112:028

Two intriguing collective phenomena occurring in suspensions of swimming microorganisms are the transition to ``bacterial turbulence'', whereby the suspension exhibits large-scale coherent flows for high enough bacterial densities, and the enhanced diffusion of passive tracer particles compared to the expected equilibrium value. In this talk, I will present results from large-scale lattice Boltzmann simulations of hydrodynamically interacting microswimmers that capture both these phenomena accurately enough to draw a number of new conclusions. The results will furthermore be compared to analytical predictions from a new stochastic kinetic theory of microswimmer suspensions that goes beyond mean-field, and thus takes into account swimmer-swimmer correlations to leading order.