title: Critical dispersion of advecting-diffusing tracers in periodic landscapes of hard-wall symmetric potentials.
abstract: Large-scale, time-asymptotic dispersion properties of diffusing tracers dragged by a uniform drive through a two-dimensional periodic lattice of hard-wall symmetric potentials are investigated. Dispersion is quantified by a typically anisotropic effective diffusivity tensor D, whose eigenvalues and eigenvectors depend on the dimensionless bare diffusivity 1/Pe for each given lattice geometry. Attention is focused on critical lattice geometries yielding sustained macroscale dispersion D([perpendicular]) along the direction orthogonal to the uniform drive in the limit where Pe→∞. A simple one-dimensional model is proposed, which predicts the anomalous scaling D([perpendicular])~1/[A(1)+A(2)log(Pe)].
authors.affiliation: Dipartimento di Ingegneria Chimica, Sapienza Università di Roma, via Eudossiana 18, 00184 Roma, Italy. stefano.cerbelli@uniroma1.it
authors.forename: S
authors.initials: S
authors.lastname: Cerbelli
mesh_terms: D003198:Computer Simulation; D018481:Convection; D004058:Diffusion; D004735:Energy Transfer; D008956:Models, Chemical; D008958:Models, Molecular; D009991:Oscillometry / Q000379:methods*; D012212:Rheology / Q000379:methods*