Mesh movement through an ALE scheme
This research was undertaken by Julian Mindel during his PhD studies at Imperial College under the supervision of Dr. J-P Latham and Prof. Chris Pain, with assistance from AMCG’s Dr. Gareth Collins, Dr. Gerard Gorman, Dr. Matt Piggott and Dr. Jiansheng Xiang.
The mesh movement method developed for FLUIDITY during the VGW project has the characteristics of Arbitrary Lagrangian Eulerian (ALE) motion. It is aimed to reduce the interpolation error introduced by adaptive mesh optimisation through reduction of the adapt frequency. At each time step, the mesh is moved in such a way as to enhance the representation of the dynamics, minimise numerical dissipation, and prevent tangling. Summarising, the three main purposes of the new mesh movement scheme are:
- To reduce any further diffusive behaviour that can’t be handled by the compressive advection scheme (i.e. sections of a fluid or material that become sub-grid scale in size).
- To allow the mesh resolution to follow the interfaces and therefore reduce the amount of adaptive mesh optimization needed. This is also aimed to reduce computational time while maintaining enhanced energetic free surface capturing.
- To prolong grid quality according to error metric values as described by Pain et al. (2001), thus protecting optimal resolution until Automated Mesh Optimisation is required.