Department of Mathematics

CoSy Lunch Seminar

  • Date: 10/17/2017 at 12:15 PM 1:00 PM
  • Location: Ångströmlaboratoriet, Lägerhyddsvägen 1 Å11167
  • Lecturer: Joakim Stenhammar, Department of Physical Chemistry, Lund University
  • Organizer: CIM
  • Contact person: Joel Dahne
  • Phone: 0762020507
  • Seminarium

Correlations and collective behaviours in suspensions of swimming microorganisms; Speaker: Joakim Stenhammar, Department of Physical Chemistry, Lund University

17 October
Speaker: Joakim Stenhammar, Department of Physical Chemistry, Lund University
Title: Correlations and collective behaviours in suspensions of swimming microorganisms
Place: Å11167
Time: 12:15 -- 13:00
Abstract:
Many microorganisms, such as bacteria and algae, have developed swimming strategies to aid them in search for food in their aqueous environments. From a hydrodynamic perspective, these organisms are interesting since swimming on the micron scale is radically different from in the macroscopic world, due to the absence of fluid inertia. Two intriguing hydrodynamic phenomena occurring in suspensions of swimming microorganisms are the transition to so-called ``bacterial turbulence'', whereby bacterial suspensions of sufficiently high density exhibit large-scale flocks and coherent flows, and the enhanced diffusion of passive tracer particles compared to the expected Brownian value. In this talk, I will present results obtained from large-scale numerical simulations of a simple model of hydrodynamically interacting microswimmers that capture both these phenomena accurately enough to draw quantitative conclusions. The results will furthermore be compared to analytical predictions from a stochastic kinetic theory of microswimmer suspensions that goes beyond mean-field, and thus takes into account swimmer-swimmer correlations, showing their importance even far below the transition to bacterial turbulence.