Propagating fronts in fluids with backaction*

We numerically study propagating fronts traveling through a long and shallow layer of fluid where the depth is parallel with the direction of gravity. The flow field is determined using a modified form of the Boussinesq equations and the propagating fronts are generated using a reaction-advection-diffusion equation with a nonlinear reaction. We explore the propagating fronts in the presence of backaction where the fronts affect the underlying fluid motion which affects the fronts and so on. We consider the case where the products are lighter than the reactants and where the reaction generates heat. We first study fronts propagating though an initially quiescent flow field. Next, we explore the propagating fronts as they travel through a cellular convective flow field that has been generated by including a constant temperature difference between the bottom and top surfaces of the fluid layer. We quantify the dynamics and geometry of the propagating fronts due to the backaction.  We explore the flow field structures near the front and investigate their influence upon the geometry of the front interface and the front velocity.