Fluid mixing by curved trajectories of microswimmers.
We consider the tracer diffusion D(rr) that arises from the run-and-tumble motion of low Reynolds number swimmers, such as bacteria. Assuming a dilute suspension, where the bacteria move in uncorrelated runs of length λ, we obtain an exact expression for D(rr) for dipolar swimmers in three dimensions, hence explaining the surprising result that this is independent of λ. We compare D(rr) to the contribution to tracer diffusion from entrainment.
The Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
Dmitri O
DO
Pushkin
Julia M
JM
Yeomans
D016825:Chlamydomonas reinhardtii / Q000502:physiology; D004926:Escherichia coli / Q000502:physiology; D008954:Models, Biological; D013550:Swimming