The Simulation of Pore Scale Fluid Flow with Real World Geometries Obtained from X-Ray Computed Tomography

Previously it has been shown mathematically that Darcy's Law for flow in porous media can be derived from the fundamental Navier-Stokes equation. With the recent improvement of X-ray Computed Tomography and robust modeling tools, it is now possible to show that pore scale fluid flow modeled by the Navier-Stokes equation can be used to derive macro parameters of Darcy's Law, such as the hydraulic conductivity. The model allows calculation of isotropy, tortuosity and dispersivity of the soil in all directions. These parameters which are used in the structural descriptions of the Darcy's phenomological Law, can now be directly calculated and compared to experimental results found in the laboratory. This study uses a 3D model of a coarse sand scanned at 4.3 um resolution. The scan data is converted into high quality tetrahedral meshes using the Image-Based Meshing tools developed by Simpleware Ltd whilst simulation of the fluid flow is carried out using the Comsol Multiphysics package.