CHEMICALLY DRIVEN CONVECTION - A SIMPLE-MODEL

Within the framework of a two species reaction-diffusion model coupled to the hydrodynamic equations we discuss how a chemical reaction driv es convective motion in a fluid layer. The model has an oscillatory in stability with vanishing wavenumber at onset. We derive from the model equations an envelope equation of Ginzburg-Landau type with complex c oefficients. To cubic order in the envelope the generated convective v elocity is slaved to the concentration variables and has no independen t dynamics. Feedback from the flow in the chemical reaction arises at higher orders in the amplitude. We compare our results with existing e xperimental data.