Abstract
We experimentally study the emergence of collective bacterial swimming, a phenomenon often referred to as bacterial turbulence. A phase diagram of the flow of 3D Escherichia coli suspensions spanned by bacterial concen tration, the swimming speed of bacteria, and the number fraction of active swimmers is systematically mapped, which shows quantitative agreement with kinetic theories and demonstrates the dominant role of hydrodynamic interactions in bacterial collective swimming. We trigger bacterial turbulence by suddenly increasing the swim ming speed of light-powered bacteria and image the transition to the turbulence in real time. Our experiments identify two unusual kinetic pathways, i.e., the one-step transition with long incubation periods near the phase boundary and the two-step transition driven by long-wavelength instabilities deep inside the turbulent phase. Our study provides not only a quantitative verification of existing theories but also insights into interparticle in teractions and transition kinetics of bacterial turbulence.
Original language | English (US) |
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Article number | eabd1240 |
Journal | Science Advances |
Volume | 7 |
Issue number | 17 |
DOIs | |
State | Published - Apr 21 2021 |
Bibliographical note
Funding Information:The research is supported by NSF CBET-1702352
Publisher Copyright:
© 2021 The Authors, some rights reserved.