Dynamics of enhanced tracer diffusion in suspensions of swimming eukaryotic microorganisms.

Dynamics of Enhanced Tracer Diffusion in Suspensions of Swimminig Eukaryotic Microorganisms

Kinetic Models for Biologically Active Suspensions

Biologically active suspensions, such as suspensions of swimming microorganisms, exhibit fascinating dynamics including large-scale collective motions and pattern formation, complex chaotic flows with good mixing properties, enhanced passsive tracer diffusion, among others. There has been much recent interest in modeling and understanding these effects, which often result from long-ranged fluid...

Diffusion and spatial correlations in suspensions of swimming particles.

Populations of swimming micro-organisms produce fluid motions that lead to dramatically enhanced diffusion of tracer particles. Using simulations of suspensions of swimming particles in a periodic domain, we capture this effect and show that it depends qualitatively on the mode of swimming: swimmers "pushed" from behind by their flagella show greater enhancement than swimmers that are "pulled" ...

Biased swimming cells do not disperse in pipes as tracers: a population model based on microscale behaviour

There is much current interest in modelling suspensions of algae and other microorganisms for biotechnological exploitation, and many bioreactors are of tubular design. Using generalized Taylor dispersion theory, we develop a population-level swimming-advection-diffusion model for suspensions of micro-organisms in a vertical pipe flow. In particular, a combination of gravitational and viscous t...

Dispersion of biased swimming microorganisms in a fluid flowing through a tube

Classical Taylor-Aris dispersion theory is extended to describe the transport of suspensions of self-propelled dipolar cells in a tubular flow. General expressions for the mean drift and effective diffusivity are determined exactly in terms of axial moments, and compared with an approximation a la Taylor. As in the Taylor-Aris case, the skewness of a finite distribution of biased swimming cells...