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 drives convective motion in a fluid layer. The model has an oscillatory instability with vanishing wavenumber at onset. We derive from the model equations an envelope equation of Ginzburg-Landau type with complex coefficients. To cubic order in the envelope the generated convective velocity is slaved to the concentration variables and has no independent dynamics. Feedback from the flow in the chemical reaction arises at higher orders in the amplitude. We compare our results with existing experimental data.