Simulation of Airfoil Stall Flows Using IDDES with High Order Schemes

摘要

The IDDES(Improved Delayed Detached Eddy Simulation) turbulence modeling is validated with the flat plate boundary layer and is used to investigate the stall flows of NACA0012 airfoil. The spatially filtered unsteady 3D Navier-Stokes equations are solved using a 5th order WENO reconstruction with a low diffusion E-CUSP scheme for the inviscid fluxes and a conservative 4th order central differencing for the viscous terms. Validation and comparison of flat plate boundary layer velocity profiles are conducted at different Mach numbers, Reynolds numbers and mesh sizes using the Spalart-Allmaras(S-A) URANS, DES97, DDES, and IDDES. The study indicates that the IDDES is accurate to predict the law of the wall regardless of the mesh size, whereas model stress depletion and log layer mismatch are observed in the DES97 and DDES computations. Stalled flows of the NACA0012 at four different angle of attacks of 5°, 17°, 45°, and 60° are simulated to investigate the capability of the URANS, DDES, and IDDES to resolve massive separated flows. At high angle of attack(AoAs), the lift and drag coefficients calculated by IDDES are much more accurate than those of the URANS computation with S-A turbulence model. The S-A URANS simulation over-predicts the drag coefficient by about 30%, whereas the IDDES accurately predicts the drag coefficient. For the massive separated flows, more realistic flow structures are resolved by the IDDES simulation.