PANS VS. LES FOR COMPUTATIONS OF THE FLOW AROUND A 3D BLUFF BODY

This paper presents comparisons between recentlyproposed Partially-Averaged Navier-Stokes(PANS) method with the Large Eddy Simulation(LES) for the flow around the Ahmed bluff body.PANS model changes seamlessly from Reynolds-Averaged Navier-Stokes (RANS) to the direct numericalsolution of the Navier-Stokes equations(DNS) as the unresolved-to-total ratios of kinetic energyand dissipation are varied. The parameter whichdetermines the unresolved-to-total kinetic energy ratiois defined based on the grid spacing and it is dynamicallyadjusted at each point at the end of everytime step. The main target of this paper is to show ifPANS obtains comparable results with LES calculationson finer meshes and improves results on coarsermeshes. In other words, the question to be answeredis whether PANS can provide the optimum solutionfor every computational mesh. This will be achievedby comparing PANS calculations on two differentcomputational meshes: 3.4 mil.(grid A), and 8.0 mil.(grid B), with LES calculations on grid A and additionaltwo grids consisting of 9.5 mil. cells (grid C)and 16.5 mil. cells (grid D)