In recent years, the oil and gas industries and the soil sciences have begun to embrace the use of µ-CT images of rocks and soils for understanding their material properties. Besides geometric analysis, material properties can also be estimated by post-processing solutions of partial differential equations on the images.
Because such materials with low porosity typically have also low permeability and small pores, it is difficult for gas or liquid to pass through them. For the classical SIMPLE algorithm it is also hard to converge to the solution of the steady state Stokes equations due to the complex connectivity. Solving the pressure correction equation was identified as the bottleneck of convergence. Using the Fast Fourier Transform (FFT) reduces the computation times significantly. The runtime and memory usage of the FFT accelerated SIMPLE method, SIMPLE-FFT, which is integrated in the GeoDict software, are compared with Fraunhofer ITWM’s inhouse Lattice Boltzmann solver, ParPac.
