Continuum Model for the Collective Behaviour of Gyrotactic Micro-Swimmers
Date:
Bottom-heavy motile micro-organisms orient themselves under the influence of gravitational and viscous torque. In a downflowing pipe, the balance between the two torques will cause the micro-organism to swim towards the centre, forming a focused beam-like structure. The structure, known as a gyrotactic plume, may further break down into blips.
In this talk, we will discuss different strategies on modelling the suspension of gyrotactic swimmers under the influence of a uni-directional flow, and why a continuum model is needed in the present case. In particular, we will focus on the use and limitation of the Generalised Taylor Dispersion Theory to create a population-level model. The use of Generalised Taylor Dispersion also leads to some newly discovered bifurcations in the plume solution, which may give some new interpretations to the plumes and blips observed in experiments.