Resonant alignment of microswimmer trajectories in oscillatory shear flows

Alexander Hope, Ottavio A. Croze, Wilson Poon, Martin Alan Bees, Mark Haw

Research output: Contribution to journalArticlepeer-review


Oscillatory flows are commonly experienced by swimming microorganisms in the environment, industrial applications and rheological investigations. We experimentally characterise the response of the alga Dunaliella salina to oscillatory shear flows, and report the surprising discovery that algal swimming trajectories orient perpendicular to the flow-shear plane. The ordering has the characteristics of a resonance in the driving parameter space. The behaviour is qualitatively reproduced by a simple model and simulations accounting for helical swimming, suggesting a mechanism for ordering and criteria for the resonant amplitude and frequency. The implications of this work for active oscillatory rheology and industrial algal processing are discussed.
Original languageEnglish
Article number051201
Pages (from-to)1-8
Number of pages8
JournalPhysical Review Fluids
Publication statusPublished - 20 Sept 2016

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