On the large-eddy simulations for the flow around aerodynamic profiles using unstructured grids

• Two LES models suitable for unstructured meshes are tested.
• A conservative formulation for collocated unstructured meshes is considered.
• Comparison with DNS results for the flow past a NACA0012 are performed.
• Good agreement is obtained, in particular for the VMS-WALE model.
• The model reproduces experimental results at high Reynolds number in stall conditions.

This paper investigates the capabilities of two subgrid-scale (SGS) models suitable for unstructured grids for predicting the complex flow in transitional separated bubbles. The flow over a NACA 0012 airfoil at Reynolds number Re = 5 × 104 and angles of attack (AOA) AOA =  5° and 8° is here considered. The SGS models investigated are: the wall-adapting eddy viscosity model within a variational multiscale method (VMS-WALE) and the QR eddy-viscosity model. Both are well suited for large-eddy simulations (LES) in complex geometries with unstructured grids. The models are assessed and compared to the results of direct numerical simulations (DNS) on the basis of first and second order statistics. Based on the good results obtained, specially with the VMS-WALE model, challenging simulations at high Reynolds numbers and various AOA are also performed. It has been found that predictions of the lift and drag coefficients agree reasonably well with experimental data.