Numerical investigation of aerodynamic performance enhancement for flatback airfoils via wavy trailing edge modifications

In the field of wind energy, effective control of airfoil drag is crucial for enhancing the power output of wind turbines. This study investigates the DU97-W-300 airfoil modified with a symmetric thickness distribution to create a flatback configuration featuring a trailing edge thickness of 10% chord. Two novel wavy trailing edge modifications were proposed. Numerical simulations employing a hybrid turbulence model and the improved delayed detached eddy simulation (IDDES) method were conducted at a Reynolds number of 3 × 10⁶ to analyze the aerodynamic performance and underlying flow mechanisms. The results demonstrate that, although the modified airfoils incur a certain loss of lift and an earlier stall onset, they significantly enhance the aerodynamic performance of the baseline flatback airfoil before stall. Specifically, a maximum drag reduction rate of 62.2% was achieved, and the oscillation amplitudes of the lift and drag coefficients were reduced by over 95%. Detailed flow field analysis reveals that the wavy trailing edge geometry primarily achieves drag reduction and suppression of aerodynamic force oscillations by inhibiting the formation of large-scale vortex structures, thereby reducing energy dissipation associated with vortex breakdown and improving the stability of the shear layer.