Now showing 1 - 2 of 2
  • Publication
    Aggregation of chemotactic organisms in a differential flow
    (American Physical Society, 2009-12) ;
    We study the effect of advection on the aggregation and pattern formation in chemotactic systems described by Keller-Segel-type models. The evolution of small perturbations is studied analytically in the linear regime complemented by numerical simulations. We show that a uniform differential flow can significantly alter the spatial structure and dynamics of the chemotactic system. The flow leads to the formation of anisotropic aggregates that move following the direction of the flow, even when the chemotactic organisms are not directly advected by the flow. Sufficiently strong advection can stop the aggregation and coarsening process that is then restricted to the direction perpendicular to the flow.
      367Scopus© Citations 2
  • Publication
    Nutrient exposure of chemotactic organisms in small-scale turbulent flows
    Micro-organisms living in a turbulent fluid environment often use directed motility to locate regions of higher than average nutrient concentrations. Here, we consider a simple continuum model for the distribution of such chemotactic particles when the particles and the chemoattractant are both advected by a turbulent flow. The influence of chemotactic sensitivity on the spatial distribution of the particles is characterized for different types of advected chemical fields. Using an effective diffusion approximation, we obtain an analytical expression for the nutrient exposure resulting from the chemotactic activity of the particles, generalizing previous results obtained for the case of phototaxis in flows. We show that the biological advantage of chemotaxis in such systems is determined by the spatial variability of the averaged chemoattractant field and the effective diffusivity of the turbulent flow.
      268Scopus© Citations 6