Marangoni flow around chemical fronts traveling in thin solution layers: influence of the liquid depth

Abstract

Surface-tension gradients, which can exist across autocatalytic chemical fronts propagating in thin layers of solution in contact with air, can induce capillary flows that are also called Marangoni flows. These flows in turn affect the spatio–temporal evolution of the concentration fields. This paper addresses the influence of the thickness of the solution layer on the chemo–hydrodynamic pattern resulting from such a coupling between autocatalytic reactions, diffusion and Marangoni effects, neglecting any buoyancy-driven effect. The system reaches an asymptotic dynamics characterized by a steady fluid vortex traveling at a constant speed with the front and deforming it. When the thickness of the fluid layer is increased, Marangoni effects are increasing, thus leading to a larger deformation of the chemical front, larger traveling speed, and more intense convection.