Simulation of Flow in Porous Media Using Coupled Pressurized-Free Surface Interconnected Conduit Network

Simulation of fluid flow in porous media has a wide range of applications including design of rockfill embankments, design of sand filters, or efficient management of ground water and oil reservoirs. Various efforts have been made during the past century to conduct such simulation modeling using both Darcy and non-Darcy laws. The nature of flow in porous media consists of a part which is under pressure and another part near the phreatic line which is exposed to atmosphere. Accordingly, a coupled pressurized-free surface flow model should be conceptualized using the network of pore body and pore throat. An effective modeling tool like an open source public domain software can then be used. In this study EPANET was modified to accommodate the nature of flow involved. For the verification purposes, a physical model was built in the Hydraulic Lab at the School of Engineering in Shiraz University. Steady state water surface profile and outflow discharge were monitored for different upstream water levels. This data were then used to calibrate and validate the developed computer model. Results showed that a satisfactory agreement between computer model and experimental records can be obtained for a wide range of upstream flow conditions. In a majority of cases, computer model captures more than 99% of variability in observed outflow discharge or water surface profile.