Displacements at Sharp Interfaces (Non-Equilibrium Flow)
When one fluid displaces another inside a porous media, the sharpness of the wetting front can determine the stability of the overall displacement. Also inherently, displacements with sharp fronts cannot be modeled using continuum multi-phase flow equations.
Qualitatively the sharpness can be explained by a competition between two different pore-filling mechanisms (called snap-off and piston-like). Previous infiltration experiments with water have shown that there exists a transition flux, where below this flux snap-off filling dominates, and above piston-like collective filling dominates. Integral to this competition is the formation of wetting layers (small conduits in the corners and edges of the pore-space) ahead of the main wetting front. We are using experimental 1-D displacements and dynamic network modeling to study the creation of these wetting layers and their affects on the dynamics of the wetting front.