title: Flow paths in wetting unsaturated flow: experiments and simulations.
abstract: The flow paths and instabilities of gravity driven infiltration of a wetting fluid into a porous medium are studied. The model experiments and simulations independently represent techniques to study the unsaturated flow in porous media, and they produce a consistent picture of how the paths of fluid transport form and depend on the relative strength of the gravitational force. The experiments, which employ a transparent and quasi-two-dimensional model, reveal that the fluid pathways contain an internal link-blob structure and increase in width with decreasing gravity. The model, which couples the well established invasion percolation model for capillary governed flow with a model that describes the viscous film flow in partially filled pores, corroborates these experimental findings.
authors.affiliation: Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo 3, Norway.
authors.forename: Eirik G
authors.initials: EG
authors.lastname: Flekkøy
authors.forename: Jean
authors.initials: J
authors.lastname: Schmittbuhl
authors.forename: Finn
authors.initials: F
authors.lastname: Løvholt
authors.forename: Unni
authors.initials: U
authors.lastname: Oxaal
authors.forename: Knut Jørgen
authors.initials: KJ
authors.lastname: Måløy
authors.forename: Per
authors.initials: P
authors.lastname: Aagaard