A local unstructured re-meshing technique for handling multi-body separation in 2D flows

Numerical simulations of bodies experiencing large relative motion, as for instance the case of two separating bodies, is a challenging task for Computational Fluid Dynamic, because mesh deformation algorithms might be inapplicable and global re-meshing techniques could be computationally too expensive. For this reason, overset methods using overlapping grids are used to tackle these kind of problems. However, even though the overset techniques are very versatile, the transfer of information between overlapping meshes is an error source that can compromise the numerical solution quality. This work describes a new computational technique, that does not use overlapping meshes, but is instead based on local remeshing and makes only limited use of interpolation between different meshes. Algorithmic details of the aforementioned technique as well as two test-cases involving the separation of bodies in high-speed flows will be presented in this paper.