Kolmogorov-Sinai entropy for the A+B-->P reaction in transitional flows

We study global decay of the bimolecular reaction A+B-->P as c(t) approximately t(-alpha) in a nonlinear transitional flow. A relationship is established between the decay exponent alpha, and a modified Kolmogorov-Sinai entropy, hr. We find that for dynamic conditions which induce relatively strong mixing, the decay exponent is alpha is proportional to ln psi(-Bhr) with B being a characteristic reactive mix-down time for the system, and psi is a space-time scaling parameter. Dynamic conditions which imply weak mixing lead to a degenerate dependence of alpha on hr. The proposed relationship between alpha on hr should be a useful link between the dynamical evolution of the flow field and reaction kinetics in vortex dominated flows.