Complex Wave Dynamics Research Articles

Dynamics of Oxidation Belousov−Zhabotinsky Waves in an Electric Field

Experiments with oxidation circular waves in a quasi-two-dimensional Belousov−Zhabotinsky reaction medium subject to an external dc electric field reveal a variety of wave dynamics scenarios involving wave splitting, reversal, annihilation, and complex pattern formation. We also investigate effects of initial concentration of reactants on the wave dynamics and find marked sensitivity related to excitability of the reaction medium. Two different variants of the Oregonator model are shown to have a common dimensionless representation providing conversion relations between corresponding rate coefficients. Modeling of the waves in an electric field is in qualitative agreement with experiments and predicts a rich structure of complex wave dynamics.

Interaction dynamics of solitary waves on a falling film

Beyond a short transition region near the inlet, waves on a falling film evolve into distinct pulse-like solitary waves that dominate all subsequent interfacial dynamics. Numerical and physical experiments indicate that these localized structures can attract and repel each other. Attractive interaction through the capillary ripples of the pulses causes two pulses to coalesce into a bigger pulse which accelerates and precipitates further coalescence. This binary interaction between an ‘excited’ pulse after coalescence and its smaller front neighbour is the key mechanism that drives the observed wave dynamics. From symmetry arguments, two dominant modes for a solitary pulse are obtained and used to develop an inelastic coherent structure theory for binary interaction between an excited pulse and its front neighbour. The theory offers a simple dynamical system that quantitatively describes the binary interaction and promises to elucidate the complex wave dynamics on a falling film.