A bistable or excitable exothermic chemical reaction can produce a traveling front of chemical reactivity upon being triggered. The dynamics of the wave propagation are greatly influenced by the amount of heat generated at the wave front, which in turn is a function of (nonlinear) reaction kinetics, enthalpy change, and extent of reaction. The chemical reaction investigated here has shown complex propagative patterns, including accelerating big waves, convective rolls, double-diffusive convection, and spatiotemporal patterns. A model devised to explain the patterns involves a laterally heated fluid layer in which the basic flow loses stability in the form of hydrothermal waves. Wave motion is preceded by a global circulation between the hot and cold regions, with the velocity being proportional to the lateral temperature gradient. In this highly exothermic reaction the spatiotemporal patterns can be explained by a stability analysis of the Bénard-Marangoni convection with lateral heating.

• Received 3 February 1995

DOI:https://doi.org/10.1103/PhysRevE.52.1606