Fluid Velocity Fluctuations in a Suspension of Swimming Protists
arXiv:1008.2770 · doi:10.1103/PhysRevLett.105.188101
Abstract
In dilute suspensions of swimming microorganisms the local fluid velocity is a random superposition of the flow fields set up by the individual organisms, which in turn have multipole contributions decaying as inverse powers of distance from the organism. Here we show that the conditions under which the central limit theorem guarantees a Gaussian probability distribution function of velocities are satisfied when the leading force singularity is a Stokeslet, but are not when it is any higher multipole. These results are confirmed by numerical studies and by experiments on suspensions of the alga Volvox carteri, which show that deviations from Gaussianity arise from near-field effects.
4 pages, 3 figures
References in corpus (3)
Cited by in corpus (16)
- Fluid Flows Created by Swimming Bacteria Drive Self-Organization in Confined Suspensions
- Green Algae as Model Organisms for Biological Fluid Dynamics
- Fluid transport by individual microswimmers
- Fluid mixing by curved trajectories of microswimmers
- Lévy Fluctuations and Tracer Diffusion in Dilute Suspensions of Algae and Bacteria
- Non-equilibrium fluctuations and nonlinear response of an active bath
- Autonomous actuation of zero modes in mechanical networks far from equilibrium
- A fine balance of chemotactic and hydrodynamic torques: when microswimmers orbit a pillar just once
- Bacteria hinder large-scale transport and enhance small-scale mixing in time-periodic flows
- Fluid transport and mixing by an unsteady microswimmer
- Stirring by swimmers in confined microenvironments
- Intermittency measurement in two dimensional bacterial turbulence
- Pair Dispersion in Dilute Suspension of Active Swimmers
- Intrinsic flow structure and multifractality in two-dimensional bacterial turbulence
- Active temperature and velocity correlations produced by a swimmer suspension
- Velocity fluctuations in a dilute suspension of viscous vortex rings