OSCILLATORY HYDRODYNAMIC FLOW DUE TO CONCENTRATION-DEPENDENCE OF SURFACE-TENSION

Using a two species reaction-diffusion model in the excitable regime c oupled to the hydrodynamic equations we discuss how a group of chemica l waves drives an oscillatory convective motion in a fluid layer The e xperiments show an oscillatory behavior of the surface flow with the m aximum velocity opposite to the direction of wave propagation. The mec hanism considered is a variation of the surface tension along a free s urface due to an inhomogeneous concentration distribution. Our results lead to an understanding of the observed oscillatory flow as well as of the large scale features observed.