Coupling OpenFOAM(R) with BoSSS, a discontinuous Galerkin solver written in C#

In this article, we present the foam-dg project, which provides a bridge between OpenFOAM® and the high-order DG (discontinuous Galerkin) framework BoSSS. Thanks to the flexibility of the coupling approach, mixed calculations where some parts of the equation system are solved in OpenFOAM® and others are solved in BoSSS are easily possible. This is showcased using the convective Cahn-Hilliard equation, where the Cahn-Hilliard part is solved in BoSSS and the Navier-Stokes part is solved in OpenFOAM®. The obtained results appear reasonable, though the main focus of this paper is to present and document the foam-dg project rather than on quantitative results.