Parallel and dynamic mesh adaptation of tetrahedral-based meshes for propagating fronts and interfaces: application to premixed combustion and primary atomization.

Thanks to the steady growth of computational resources and a large effort on solver optimization, Large-Eddy Simulation (LES) of realistic systems has become attainable. In these systems, turbulent multi-physics flows involve a large range of scales that need to be resolved by the mesh to capture the proper flow dynamics. Adaptive or dynamic mesh adaptation (AMR) is an appealing technique to reduce the modeling errors in LES. AMR of tetrahedral-based meshes for LES is difficult as it requires numerous mesh topology changes and high-quality grids to resolve the turbulent scales that are close to the cut-off frequency of the mesh. A parallel AMR strategy has been developed recently [Bénard et al., IJNMF 2015] in the YALES2 flow solver [www.coria-cfd.fr]. It combines adaptation and repartitioning steps to enable the AMR of massive grids counting billion cells exploiting up to tens of thousand cores. Mesh adaptation relies on the work of Dapogny et al. [JCP 2014] available in the MMG library [www.mmgtools.org]. The presentation will focus on the parallel adaptation strategy for both volume and surface meshes, its optimization on modern super-computers and on various academic and industrial applications related to premixed turbulent combustion and primary atomization.