Numerical investigation of S809 airfoil aerodynamic characteristics

Abstract

Airfoil S809 has been used for design of series of blades for experimental determination of wind turbine aerodynamic loads. In order to validate aerodynamic models of wind turbine rotors based on momentum or vortex theory it is crucial to have reliable aerodynamic data on blade sections. On the other hand, for full three dimensional rotor computations based on Reynolds averaged Navier-Stokes equations (RANS), it is necessary to calibrate chosen numerical model in two dimensional cases. Therefore, computational study of flow around S809 airfoil was conducted using RANS in ANSYS FLUENT 14.5. Turbulence models k-ω SST and γ-Reθ (Transition SST) were used in order to investigate their capabilities to predict airfoil aerodynamic characteristics. The obtained results were compared to lift and drag coefficients from available wind tunnel tests. Flow domain was discretized both using fully structured and unstructured hybrid grid and the results have been compared. In performed computations non-dimensional distance from the wall y+ was below 1. Laminar to turbulent boundary layer transition was captured. In addition to flow simulations based on finite volume method, viscous-inviscid method available in X-Foil was used to compute airfoil performance.