Density fingering of an exothermic autocatalytic reaction

The density fingering of an exothermic autocatalytic reaction, where the solutal and thermal contribution to density changes were oppositely signed, was studied. The exothermic autocatalytic model was based on a vertically oriented two-dimensional porous media or Hele-Shaw cell. The competition between the solutal and thermal contribution led to thermal plumes for ascending autocatalytic fronts. For some parameter values, such as fingers of constant amplitude and wavelength, the descending fronts were found to behave strikingly different. Dispersion curves and nonlinear dynamics were used for discussing the observed differences between the ascending and descending fronts behaviors.