VOFTools 5: An extension to non-convex geometries of calculation tools for volume of fluid methods
The VOFTools library includes useful tools for performing the geometrical operations that typically arise in volume of fluid (VOF) methods. We present a major improvement of VOFTools to extend its use to non-convex geometries without the need for costly convex-decomposition techniques. A thorough adaptation of the different routines has been carried out to meet the challenges of the new geometries and to maintain, and even improve, the efficiency and robustness of the previous tools. Specifically, we upgraded the routines for (1) truncating a polyhedron with a half space, (2) computing the interface position to cut off a certain volume fraction from a cell in PLIC (piecewise linear interface calculation) reconstruction and (3) computing the volume of a material body, defined by an implicit function, that is contained inside a mesh cell. To assess the performance of the supplied routines, different tests, which are provided in FORTRAN and C, were implemented for several 2D and 3D non-convex geometries.