Stability characteristics of different aerofoil flows at Rec=150,000 and the implications for aerofoil self-noise

Abstract

Three compressible-flow direct numerical simulations (DNS) of aerofoils were conducted at a chord based Reynolds number of Rec=150,000: a Controlled-Diffusion (CD) aerofoil at two incidences and an untripped NACA 6512-63 aerofoil at 0∘ angle of attack (AoA). The aim of the simulations was to help improve the understanding of the generation mechanisms of aerofoil self-noise. To this end, the time-averaged flows around the aerofoils were investigated using a multi-dimensional global stability analysis based on the response to very low-amplitude hydrodynamic initial pulses. For the CD aerofoil at 5∘ AoA and the untripped NACA 6512-63 aerfoil at 0∘ AoA, the base flows are found to be globally un..