Compressible Large Eddy Simulation Using Unstructured Grids

We present an algorithm for compressible Large Eddy Simulation (LES) using unstructured tetrahedral grids. Two methods for simulation of the subgrid scale stresses are examined. The first method is the Monotone Integrated Large Eddy Simulation (MILES) technique of Boris, Oran and Grinstein, whereby the energy transfer from the resolved scales to the subgrid scales is modeled using the inherent dissipation of the numerical algorithm. The second method is a hybrid technique combining MILES with a Smagorinsky eddy viscosity model for the subgrid scale stresses. The inviscid fluxes are determined by Godunov's second method or Roe's method. Two different second-order accurate function reconstruction techniques have been evaluated. The subgrid scale stresses are computed using a second-order accurate method based on Gauss' theorem. A second-order Runge-Kutta method is employed for the temporal integration. Simulation of the decay of incompressible isotropic turbulence has been performed for ..