EXPERIMENTAL STUDIES OF ADVECTION-REACTIONDIFFUSION SYSTEMS

摘要

We present the results of experiments on the effects of chaotic fluid mixing on the dynamics of reacting systems. The flow studied is a chain of alternating vortices in an annular geometry with drifting and/or oscillatory time-dependence. The dynamical system is the oscillatory or excitable state of the well-known Belousov-Zhabotinsky chemical reaction. Results from two sets of experiments are as follows: (1) Fronts propagating in the oscillating vortex chain are found to mode-lock onto the frequency of the external oscillations. It is also found that the presence of a significant "wind" (drift of the vortices in the lab frame) causes fronts propagating against the wind to freeze. (2) Synchronization of oscillating reactions in an extended flow (vortex chain with large number of vortices) is found to be enhanced significantly by the presence of superdiffusive transport characterized by Levy flights that connect different parts of the flow.