Two computational studies of a flatback airfoil using non-zonal and embedded scale-resolving turbulence modelling approaches

Abstract

The contribution presents results from two computational studies conducted by Upstream CFD and ENERCON, which aim to evaluate their respective CFD methodologies for the aerodynamics and aeroacoustics prediction of a flatback airfoil with 35% relative thickness. The CFD is validated against data from two comprehensive experimental campaigns conducted in the NWB facility operated by the German-Dutch Wind Tunnels Foundation (DNW), which include measurements of mean force coefficients, static and total pressure distributions in the wake region, unsteady surface pressures and farfield sound emission. In both numerical studies, scale-resolving approaches based on detached-eddy simulation are utilised, where a comparison is drawn between a purely non-zonal use of the model in which attached boundary layers are fully modelled via RANS and a zonal use with synthetic turbulence being injected into the boundary layers upstream of the trailing edge. First, the aerodynamic flow fields are analysed, showing good agreement with the reference measurements. Farfield noise is then predicted from solid and permeable Ffowcs-Williams and Hawkings surfaces, where both the dominant shedding tone as well as broadband levels compare well with microphone array data.