Capillary Network Model: Capillary Power and Effective Permeability
  A simple model of two-phase flow in porous media is presented. A connection is made to statistical mechanics by applying capillary power as a constraint. Stochastic sampling is then used to test the validity of this approach. Good agreement is found between stochastic sampling and time stepping for flow-rates above a transition value. 
Morten Gr{\o}va
cond-mat.soft cond-mat.stat-mech physics.comp-ph physics.flu-dyn