Dynamic Mesh Handling in OpenFOAM

Abstract

Extension of static mesh numerics in a CFD solver to cases with deforming boundaries considerably expands the scope of its use. Dynamic mesh handling includes deforming mesh cases, where the number and connectivity of mesh elements remains unchanged; and topological changes, where mesh size and connectivity varies during the simulation. Cases where the boundary deformation itself represents a part of the solution demand special attention: here, mesh handling needs to be fully automatic. This paper describes dynamic mesh support in OpenFOAM, a C++ object-oriented library for numerical simulations in continuum mechanics. Unlike other tools, where dynamic mesh support is usually retro-fitted, object-oriented dynamic mesh engine has been built up from ground-up. Emphasis is given polyhedral cell support in mesh analysis and discretisation, vertex-based automatic mesh motion techniques and hierarchical design of topology morphing engine. The paper is completed with examples of solution-dependent motion with large boundary deformation.