This work investigates the stability of a power-law fluid flowing in a fluid–porous channel using a one-domain Volume-Averaged Navier–Stokes framework. A smooth porosity transition is employed to model the Brinkman layer, enabling a unified description of the flow. The base flow is computed numerically, followed by a linear stability analysis to examine the evolution of disturbances. The formulation is validated in the Newtonian limit through comparison with classical stability results, demonstrating the reliability of the approach.
