Instabilities in elastic–plastic fluid-saturated porous media: harmonic wave versus acceleration wave analyses

A linearized analysis of the stability of the ~ow in elastic plastic ~uid!saturated porous media with incompressible constituents is performed[ A relationship is established between the results of this analysis and the results of analyses based on acceleration waves performed by Loret and Harireche Journal of the Mechanics and Physics of Solids 28\ 458 595 "0880# and by Loret et al[ International Journal of Solids and Structures 23\ 0472 0597 "0886# ^ a justi_cation is found for the growth of the acceleration waves in the non!associative case when their speeds are real and a clari_cation is provided relative to the growth or decay of waves in the interior of ~utter regions