Random walks, random flows, and enhanceddiffusivityin advection-diffusion equations
Michael Eugene Taylor · Discrete and Continuous Dynamical Systems - B · 2012
We study the phenomenon of enhanced diffusivity,introduced by G. I.Taylor,for a class of advection-diffusion equations, modeling, forexample, the spread of an ink drop in a fluid engaged in Poiseuille flow.We consider such flow in a pipe of general cross section, and computevariances and covariances of certain random flows associated with theadvection-diffusion. We examine both long time behavior, including acentrallimit theorem, and short time asymptotics.