Linear stability of radial displacements in porous media: Influence of velocity-induced dispersion and concentration-dependent diffusion

A parametric study is conducted in order to investigate the influence of (a) velocity dependent dispersion, and (b) concentration-dependent diffusion on the stability of miscible porous media displacements in the radial geometry. Numerical solutions for the base concentration profile demonstrate that velocity induced dispersion dominates for short times and large Peclet numbers. For large times, the growth rates approach those obtained when only molecular diffusion is taken into account. Concentration-dependent diffusion coefficients are seen to modify the mobility profiles of the base flow, and to shift the eigenfunctions into more or less viscous environments. This results in a destabilization for nearly all Peclet values and mobility ratios. (C) 2004 American Institute of Physics.