Chemical wave propagation in Hele-Shaw cells and porous media

Chemical waves induce density gradients in fluids which may lead to convection. This paper studies the convective effects on chemical waves propagating in porous media or in fluids confined between two parallel vertical walls. Chemical waves in the iodate-arsenous acid system are modeled with a one variable reaction-diffusion equation. The fluid flow is modeled using Darcy's law. A linear stability analysis on convectionless fronts shows a transition to convection. The full nonlinear equations describing the convective front are solved numerically on a vertical slab. Convective fronts propagate faster than convectionless fronts. Near the onset of convection, the fronts are raised on one side of the slab and lowered on the opposite side. Away from the onset, the fronts are raised at the middle of the slab with the opposing sides at the same height.