Research on the effect of trail-edge improvement on airfoils performance for wind turbine

A numerical simulation was used for researching the aerodynamic characteristics of wind turbine including NACA4412 airfoil, a modified NACA 4412 airfoil with a Gurney flap of 2% chord height and another modified NACA 4412 airfoil with a blunt of 2% chord thickness. It used the SIMPLE algorithm of finite element method to compute and analysis with coming wind speed was 9.5m/s and the attack angle from 0 to 25 degrees. Aerodynamic characteristic computational results showed that a strong downwash effect was produced by the modified airfoil with the blunt trailing edge, which changed the pressure distribution on the pressure and suction surface significantly. Therefore compared with the original NACA 4412 aerofoil, the lift and liftdrag ratio of the modified NACA 4412 airfoil was enhanced remarkably and the stall attack angle was increased. It had a spectrum analysis by noise mechanism of airfoils and the frequency spectrum of the noise signal, and the aerodynamic noise calculate results indicated that there existed highly directional radiation of the airfoils and the modified airfoils were reduced remarkably. It provided a reliable theory for low noise optimal design and noise prediction of wind turbine.