The shape stability of the reaction interface for reactive flow in a porous medium is investigated.
Previous work showed that the Reaction-Infiltration Instability could cause the reaction
zone to lose stability when the Peclet number exceeded a critical value. The new feature of this
study is to include a velocity-dependent hydrodynamic dispersion. A mathematical model for
this phenomenon is given in the form of a moving free-boundary problem. The spectrum of
the linearized problem is obtained, and the related analysis and numerical calculations show
that the onset of the instability is not eliminated by the new dispersive terms. The details of
analysis show that the instability is reduced especially by the transverse dispersion.