Taylor dispersion in two-dimensional bacterial turbulence

Abstract

In this work, single particle dispersion was analyzed for a bacterial turbulence by retrieving the virtual Lagrangian trajectory via numerical integration of the Lagrangian equation. High-order displacement functions were calculated for cases with and without mean velocity effect. Two-regime power-law behavior for short and long time evolutions were identified experimentally, which were separated by the Lagrangian integral time. For the case with the mean velocity effect, the experimental Hurst numbers were determined to be $0.94$ and $0.97$ for short and long times evolutions, respectively. For the case without the mean velocity effect, the values were $0.88$ and $0.58$. Moreover, very weak intermittency correction was detected. All measured Hurst number were above $1/2$, the value of the normal diffusion, which verifies the super-diffusion behavior of living fluid. This behavior increases the efficiency of bacteria to obtain food.

arXiv comment20 pages with 13 figures

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Cited by in corpus (4)

• Vortex dynamics and Lagrangian statistics in a model for active turbulence
• Microbial transport and dispersion in heterogeneous flows created by pillar arrays
• Cascades and Kolmogorov's lognormal scaling in two-dimensional bacterial turbulence
• Anomalous diffusion in a randomly modulated velocity field