voFoam - A geometrical Volume of Fluid algorithm on arbitrary unstructured meshes with local dynamic adaptive mesh refinement using OpenFOAM

摘要

A new parallelized unsplit geometrical Volume of Fluid (VoF) algorithm withsupport for arbitrary unstructured meshes and dynamic local Adaptive MeshRefinement (AMR), as well as for two and three dimensional computation isdeveloped. The geometrical VoF algorithm supports arbitrary unstructured meshesin order to enable computations involving flow domains of arbitrary geometricalcomplexity. The implementation of the method is done within the framework ofthe OpenFOAM library for Computational Continuum Mechanics (CCM) using the C++programming language with modern policy based design for high program codemodularity. The development of the geometrical VoF algorithm significantlyextends the method base of the OpenFOAM library by geometrical volumetric fluxcomputation for two-phase flow simulations. For the volume fraction advection, a novel unsplit geometrical algorithm isdeveloped, which inherently sustains volume conservation utilizing uniqueLagrangian discrete trajectories located in the mesh points. This practicecompletely eliminates the possibility of an overlap between the flux polyhedraand hence significantly increases volume conservation. A new efficient(quadratic convergent) and accurate iterative flux correction algorithm isdeveloped, which avoids topological changes of the flux polyhedra. Ourgeometrical VoF algorithm is dimension agnostic, providing automatic supportfor both 2D and 3D computations, following the established practice inOpenFOAM. The geometrical algorithm used for the volume fraction transport hasbeen extended to support dynamic local AMR available in OpenFOAM. Furthermore,the existing dynamic mesh capability of OpenFOAM has been modified to supportthe geometrical mapping algorithm executed as a part of the dynamic local AMRcycle. The method implementation is fully parallelized using the domaindecomposition approach.