NUMERICAL INVESTIGATION ON AERODYNAMIC NOISE OF WIND TURBINE AIRFOILS WITH SERRATED GURNEY FLAP

To explore the influence of the trailing edge of serrated Gurney flap (SGF) on the aerodynamic performance and noise of wind turbine airfoils, the SST k-ω turbulence model is adopted to numerically study the NACA0018 airfoil with Gurney flap (GF) and SGF. The effects of serration height and width on aerodynamic performance and static pressure distribution are examined. The noise and vortex structure of SGF with optimal aerodynamic performance are investigated by LES. The results show that SGF can effectively improve the lift coefficient and delay stall of the airfoil, and SGF-0.8-6.7 model can increase the maximum lift-to-drag ratio by 8.61% and the stall angle of attack (AOA) by 3°, which presents a preferred performance in widening the high lift range and deferring the stall. There is no significant difference between the upper and lower airfoil noise of SGF, and the average sound pressure level rises with increasing AOA. The wake noise of SGF-0.8-6.7 model increases and then decreases with increasing AOA, decreases with lengthening distance. The radiation noise presents a typical dipole shape, the noise of GF reduces under small AOAs but raises under large AOAs, while that of SGF is lower than baseline under all AOAs, with the maximum reduction of 10.2 dB. The wake vortices of SGFs are more stable and orderly, the energy consumption and loss are reduced, resulting in significant improvements in the aerodynamic performance and noise. © 2023 Science Press. All rights reserved.