title: Gyrotaxis in a steady vortical flow.
abstract: We show that gyrotactic motility within a steady vortical flow leads to tightly clustered aggregations of microorganisms. Two dimensionless numbers, characterizing the relative swimming speed and stability against overturning by vorticity, govern the coupling between motility and flow. Exploration of parameter space reveals a striking array of patchiness regimes. Aggregations are found to form within a few overturning time scales, suggesting that vortical flows might be capable of efficiently separating species with different motility characteristics.
authors.affiliation: Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: William M
authors.initials: WM
authors.lastname: Durham
authors.forename: Eric
authors.initials: E
authors.lastname: Climent
authors.forename: Roman
authors.initials: R
authors.lastname: Stocker
mesh_terms: D001696:Biomechanical Phenomena; D055592:Biophysical Phenomena; D009068:Movement / Q000502:physiology*; D013550:Swimming / Q000502:physiology; D014783:Viscosity; D014871:Water Microbiology