Reaction-diffusion front speeds in random shears

We analyze asymptotic laws of front speed enhancement in stationary ergodic random shears for the Fisher-KPP nonlinearity on the entire plane. This is possible through a Hamilton-Jacobi reduction and Liapunov exponent analysis of the so called parabolic Anderson problem. Numerical computation of ensemble averaged front speeds in channel domains shows enhancement behavior for more general nonlinearities in the presence of random shears. We show modified asymptotic laws observed numerically, and speed statistics.