Numerical study of an iced airfoil using window-embedded RANS/LES hybrid method

Unsteady and massive flow separation around a GLC-305 airfoil with a 22.5 min leadingedge horn ice accretion is numerically investigated using Delayed Detached-Eddy Simulation (DDES) based on shear layer stress transport model (SST). To resolve abundant turbulent structures, a low dissipation scheme called SLAU/MDCD is applied. The lift coefficient of the iced airfoil is well predicted by current approach with a relative error 1.2%, better than by 2D steady RANS, Dynamic Hybrid RANS/LES method (DHRL) and Zonal Detached Eddy Simulation method (ZDES). Although all methods underpredict the pressure plateau on the suction surface, DDES with low dissipation scheme reproduces the pressure plateau higher than the other methods, which shows better agreement with the experimental data. According to the time-averaged velocity field, the current DDES shows a reattachment position only slightly shorter instead of longer observed by other numerical studies than experimental result. Consequenly, low dissipation scheme is necessary to predict the separation bubble accurately. Finally, we conclude that DDES based on low disspation scheme is helpful to speed up the Kelvin-Helmholtz instability of free shear layer and capture abundant turbulent structures.