High-fidelity simulations of the flow around a NACA 4412 wing section at high angles of attack

Abstract

This study uses high-resolution large-eddy simulations (LES) to investigate the turbulent flow around a NACA 4412 wing profile at multiple Reynolds numbers based on chord length and free-stream velocity ( = 2×105, 4×105 and 106) and angles of attack (AoA= 5◦, 8◦, 11◦ and 14◦). The introduction of adaptive mesh refinement (AMR) and non-conformal meshing into the spectral-element-method code Nek5000 enabled the simulations at higher AoAs exhibiting flow separation by enabling the use of wider domains, allowing to capture the largest turbulent scales associated with flow separation. The results provide a detailed database– including integral quantities, velocity statistics and spectra– which may be used for the evaluation of lower-fidelity turbulence models. Furthermore, closer inspection of specific turbulent-boundary-layer (TBL) profiles allows us to discern between pressure-gradient (PG) and Reynolds-numbers effects on TBLs, showing that balances the PG, by reducing the impact of PG on the flow. Lastly, we assess the influence of flow history on TBLs, showing that a consistent flow history over an extended length is needed for TBLs to exhibit comparable profiles and characteristics.