Grid Adaptation of Multiphase Fluid Flow Solver in Porous Medium by OpenFOAM

The focus of the present work is to develop the two-phase immiscible and incompressible fluid flow solver for porous medium using the object-oriented (C++) Open Source Computational Fluid Dynamics (CFD) toolbox known as OpenFOAM. The reason for choosing the OpenFOAM framework is first elaborated by looking into the history of the programming concepts used in the development of numerical simulators. The scopes and limitations of the existing solvers in the OpenFOAM for the porous medium are looked in detail for identifying the elements of adding any new features to it. The pressure-saturation formulation is the mathematical approach adopted in this present study. In the immiscible two-phase flow, both the wetting phase saturation and the non-wetting phase pressure are solved implicitly using the IMPSAT (IMplicit in Pressure and SATuration) numerical formulation. Additionally, the coupled effect of IMPSAT with Adaptive Mesh Refinement (AMR) technique and the specialized two-dimensional Adaptive Mesh Refinement (2DAMR) technique for 2D problems are investigated. The superiority of using 2DAMR over the existing default hex-mesh cutter algorithm is quantified. The numerical solution is validated with standard Buckley-Leverett semi-analytical solution for one dimension and two-dimension problems. Also, the developed solver is tested for the three-dimensional case.