Fluctuation-dominated kinetics under stirring

Abstract

We investigate the effects of stirring on the kinetics of the A + B → 0 reaction under stoichiometrical conditions in 2D. We consider both a steady eddy-lattice flow and a random flow mimicking turbulence. In both situations complex decay patterns are detected. Only an intermediate stage of the reaction is dominated by mixing. The long-time behavior shows fluctuation-dominated kinetics, c ( t ) ∝ t − 1 / 2 , governed by effective diffusion. For the case of an eddy-lattice flow a very slow intermediate regime emerges, c ( t ) ∝ t − 1 / 4 , which is associated with the closed topology of flow lines.