Plume and finger regimes driven by an exothermic interfacial reaction

Studies of convection in fluids, like Rayleigh-Benard-, or Benard-Marangoni convection have strongly influenced our understanding of pattern formation and turbulence. In these systems energy is supplied by an external temperature difference applied across a given vertical length scale. However, this situation is not representative for a variety of systems occurring in nature. Here, the dynamics is driven by internal sources of energy and the selected length scale is a part of the solution of the problem. The study of such systems is interesting from both a fundamental point of view and with respect to potential applications of basic research. Promising candidates for such studies are systems involving chemical reactions. Consumption of educts and the release of reaction enthalpy are sources of solutal and thermal gradients. Hydrodynamic instabilities, driven by these gradients, can drastically alter the chemical reaction rate. We demonstrate that a rather simple interfacial neutralization reaction can develop an unexpected coupling of different hydrodynamic instabilities. (orig.)