Fluid dynamics of self-propelled microorganisms, from individuals to concentrated populations

Luis H. Cisneros, Ricardo Cortez, Christopher Dombrowski, Raymond E. Goldstein, John O. Kessler

Research output: Contribution to journalArticlepeer-review

205 Scopus citations


Nearly close-packed populations of the swimming bacterium Bacillus subtilis form a collective phase, the "Zooming BioNematic" (ZBN). This state exhibits large-scale orientational coherence, analogous to the molecular alignment of nematic liquid crystals, coupled with remarkable spatial and temporal correlations of velocity and vorticity, as measured by both novel and standard applications of particle imaging velocimetry. The appearance of turbulent dynamics in a system which is nominally in the regime of Stokes flow can be understood by accounting for the local energy input by the swimmers, with a new dimensionless ratio analogous to the Reynolds number. The interaction between organisms and boundaries, and with one another, is modeled by application of the methods of regularized Stokeslets.

Original languageEnglish (US)
Pages (from-to)737-753
Number of pages17
JournalExperiments in Fluids
Issue number5
StatePublished - Nov 2007
Externally publishedYes

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes


Dive into the research topics of 'Fluid dynamics of self-propelled microorganisms, from individuals to concentrated populations'. Together they form a unique fingerprint.

Cite this