title: Numerical approach to frictional fingers.
abstract: Experiments on confined two-phase flow systems, involving air and a dense suspension, have revealed a diverse set of flow morphologies. As the air displaces the suspension, the beads that make up the suspension can accumulate along the interface. The dynamics can generate "frictional fingers" of air coated by densely packed grains. We present here a simplified model for the dynamics together with a new numerical strategy for simulating the frictional finger behavior. The model is based on the yield stress criterion of the interface. The discretization scheme allows for simulating a larger range of structures than previous approaches. We further make theoretical predictions for the characteristic width associated with the frictional fingers, based on the yield stress criterion, and compare these to experimental results. The agreement between theory and experiments validates our model and allows us to estimate the unknown parameter in the yield stress criterion, which we use in the simulations.
authors.affiliation: Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway.|Institut de Physique du Globe de Strasbourg, University of Strasbourg/EOST, CNRS, 5 rue Descartes, F-67084 Strasbourg Cedex, France.
authors.forename: Jon Alm
authors.initials: JA
authors.lastname: Eriksen
authors.affiliation: Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway.|Institut de Physique du Globe de Strasbourg, University of Strasbourg/EOST, CNRS, 5 rue Descartes, F-67084 Strasbourg Cedex, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Toussaint
authors.affiliation: Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway.
authors.forename: Knut Jørgen
authors.initials: KJ
authors.lastname: Måløy
authors.affiliation: Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway.
authors.forename: Eirik
authors.initials: E
authors.lastname: Flekkøy
authors.affiliation: College of Engineering, Swansea University, Bay Campus, Swansea SA1 8EN, United Kingdom.
authors.forename: Bjørnar
authors.initials: B
authors.lastname: Sandnes