Parallel adaptive mesh refinement for large-eddy simulations of turbulent flows

Abstract

In this paper a parallel adaptive mesh refinement (AMR) strategy for large eddy simulations (LES) of turbulent flows is presented. The underlying discretization of the Navier-Stokes equations is based on a finite-volume symmetry-preserving formulation, with the aim of preserving the symmetry properties of the continuous differential operators and ensure both, stability and conservation of kinetic-energy balance. The conservation properties are tested for the meshes resulting from the AMR process, which typically contain transitions between zones with different level of refinement. Our AMR scheme applies a cell-based refinement technique, with a physics-based refinement criteria based on the variational multi-scale (VMS) decomposition theory. The overall AMR process, from the selection of the cells to be refined/coarsened till the pre-processing of the resulting mesh, has been implemented in a parallel code, for which the parallel performance has been attested on an AMD Opteron based supercomputer. Finally, the robustness and accuracy of our methodology is shown on the numerical simulation of the turbulent flow around a square cylinder at Re = 22,000 and the turbulent flow around two side-by-side square cylinders at Re = 21,000.