A Cartesian non-boundary fitted grid method on complex geometries and its application to the blood flow in the aorta using OpenFOAM

Abstract

The aim of this paper is to develop a new non-boundary fitted (NBF) Cartesian grid method to compute flows in a complex geometry such as that found in a human aorta. The algorithm is based on the volume of fluid (VOF) colour function in a regular Cartesian grid through the open source OpenFOAM platform. The solid was treated as a fluid with very high viscosity to theoretically reduce its deformability, and subsequently satisfy a no-slip condition at the boundary. We also introduced the artificial term of the colour function into an algebraic system of momentum equations, which had a significant impact on the non deformability of solid domain and originality of this study. The developed solver, NBF-VOF, is then thoroughly validated using a variety of numerical and experimental results available in the literature Finally, we demonstrated the applicability of our code on flows in a complex geometry based on patient-specific image data robustly without the need for complex meshing generation procedures that conventional boundary fitted (BF) methods do.