title: Control mechanisms for the global structure of scalar dispersion in chaotic flows.
abstract: Scalar dispersion has complex interactions between advection and diffusion that depend on the values of the scalar diffusivity and of the (possibly large) set of parameters controlling the flow. Using a spectral method which is three to four orders of magnitude faster than traditional methods, we calculate the fine-scale structure of the global solution space of the advection-diffusion equation for a physically realizable chaotic flow. The solution space is rich: spatial pattern locking, an order-disorder transition, and optima in dispersion rates that move discontinuously with Peclét number and boundary condition type are some of the discoveries. We uncover the mechanisms which control pattern locking and govern the global structure of dispersion across the parameter space and Peclét number spectrum.
authors.affiliation: CSIRO Mathematics, Informatics and Statistics, Box 56 Graham Rd, Highett Victoria 3190, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lester
authors.affiliation: CSIRO Materials Science & Engineering, Box 56 Graham Rd, Highett Victoria 3190, Australia.
authors.forename: Guy
authors.initials: G
authors.lastname: Metcalfe
authors.affiliation: Dept. Mechanical and Aerospace Engineering, Monash University, Clayton South Victoria 3168, Australia.
authors.forename: Murray
authors.initials: M
authors.lastname: Rudman
mesh_terms: D004058:Diffusion; D008962:Models, Theoretical; D009038:Motion; D017711:Nonlinear Dynamics