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Communication Dans Un Congrès Année : 2019

Correlation lengths in turbulent bacterial suspensions

Résumé

Dense suspensions of swimming bacteria display remarkable properties such as the appearance of collective motion, i.e. local bacterial ordering associated with a characteristic correlation length-scale, reminiscent of turbulent flow behaviour. Here, we investigate this phenomenon as a function of system-size and bacterial concentrations using video microscopy over large fields of view (up to 3mm X 4mm). Using particle image velocimetry, we calculate the spatial correlation of the velocity vectors and extract a characteristic length scale L. At sufficiently, high bacterial concentrations, we found the length L is proportional to the smallest system size, i.e. here the height of the glass capillary. However, we found no saturation of L towards large system-sizes and L can reach ~500 µm, which is ~5x larger than the currently largest L reported for bacterial suspensions. This suggests the absence of an intrinsic length-scale of dense populations of such ‘pusher-like’ swimmers.
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Dates et versions

hal-04489968 , version 1 (05-03-2024)

Identifiants

  • HAL Id : hal-04489968 , version 1

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Carine Douarche, Vincent Martinez, Pierre-Henri Delville, Jana Schwarz-Linek, Jochen Arlt, et al.. Correlation lengths in turbulent bacterial suspensions. International Soft Matter Conference, Jun 2019, Edinburgh (Scotland), United Kingdom. ⟨hal-04489968⟩
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