Type of Software
A set of C and Fortran computer programs have been developed for computing the permeability of three-dimensional porous media under incompressible Stokes flow conditions. While currently being employed to simulate the permeability of model pervious concretes, the codes have been utilized in the past on a wide variety of model and real (computer tomography) three-dimensional microstructures.
For many years, research in the Materials and Structural Systems Division (formerly the Materials and Construction Research Division) at the National Institute of Standards and Technology (NIST) has focused on understanding the relationship between microstructure and properties, particularly for cement-based materials. For many materials, one key material property is their resistance to fluid flow under a pressure gradient, e.g., their permeability. For the case of laminar (slow, incompressible) flow, the fluid flow can be conveniently described by the linear Stokes equations. This program presents a set of computer codes written in the C and Fortran programming languages to accomplish two purposes: 1) a pre-processor written in C to convert a model or real three-dimensional microstructure (represented by a three-dimensional set of voxels) into lists of coordinates representing the voxels where pressures, x-velocity, y-velocity, or z-velocity components will be present and 2) a set of Fortran programs to numerically solve the linear Stokes equations in three dimensions, using a finite difference scheme in conjunction with the artificial compressibility relaxation algorithm.
Fortran and/or C
NISTIR 7416: A Stokes Permeability Solver for Three-Dimensional Porous Media
The U.S. Department of Commerce makes no warranty, expressed or implied, to users of the three-dimensional Stokes solver and its associated computer programs, and accepts no responsibility for its use. Users of these computer programs assume sole responsibility under Federal law for determining the appropriateness of its use in any particular application; for any conclusions drawn from the results of its use; and for any actions taken or not taken as a result of analyses performed using these tools.
Users are warned that these codes are intended for use only by those competent in the field of computational materials science and are intended only to supplement the informed judgment of the qualified user. The software package may or may not have predictive value when applied to a specific set of factual circumstances. Lack of accurate predictions by the model could lead to erroneous conclusions with regard to materials selection and design. All results should be evaluated by an informed user.