Sharp Asymptotics for KPP Pulsating Front Speed-Up and Diffusion Enhancement by Flows

摘要

We study KPP pulsating front speed-up and effective diffusivity enhancement by general periodic incompressible flows. We prove the existence of and determine the limits c(e)*(A)/A and D-e(A)/A(2) as the flow amplitude A -> infinity, with c(e)*(A) the minimal front speed and D-e(A) the effective diffusivity in direction e.