title: Mixing efficiency in an excitable medium with chaotic shear flow.
abstract: The effect of a time-periodic chaotic shear flow on an excitable chemical medium is studied numerically. Stirring effects on pattern formation strongly depend on the shear amplitude and the ratio of the advective and chemical time scales (Damköhler number, Da). We have observed that the wave period increases with decreasing Da below some critical value, afterwards the period decreases until complete wave annihilation. In the last case, before final extinction, a set of uncorrelated, nonstationary excitable dots survive, whose number depends on the mixing rate. Insights on the nature of this critical behavior are obtained through the calculation of the mixing efficiency of the flow.
authors.affiliation: Group of Nonlinear Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain. perez.vicente@cesga.es
authors.forename: Vicente
authors.initials: V
authors.lastname: Pérez-Muñuzuri
authors.forename: Guillermo
authors.initials: G
authors.lastname: Fernández-García