We report an experimental study of chaotic mixing of chemically reacting species, for first- and second-order reactions, in a system composed of a pair of like-sign vortices, oscillating periodically in time. For the second-order reaction, we find that the overall reactivity is enhanced compared to homogeneous mixing. This provides experimental evidence that chaotic mixing may increase the overall reaction rate for second-order reactions. We offer a method to estimate the global reactivity, which underlines the role of the concentration filaments formed, in the system, by the chaotic process.

• Received 10 February 1997

DOI:https://doi.org/10.1103/PhysRevE.56.2287