Rachel Bearon

Revisiting Jeffery orbits; the importance of shape for micro-organism transport

Classical work of Jeffery from 1922 established how at low Reynolds number, ellipsoids in steady shear flow undergo periodic motion with non-uniform rotation rate, termed 'Jeffery orbits'. I will present two problems where Jeffery orbits play a critical role in understanding the transport and aggregation of rod-shaped organisms. I will discuss the trapping of motile chemotactic bacteria in high shear and the vertical transport of chain-forming plankton.