Aerodynamic Performance Enhancement of Tiltrotor Aircraft Wings Using Double-Row Vortex Generators

To improve the aerodynamic performance of tiltrotor aircraft, the flow characteristics of the V-22 airfoil without and with one, two parallel rows of vortex generators (VGs) were investigated using numerical simulation methods. The results were obtained with three-dimensional compressible Reynolds-averaged Navier–Stokes equations, and the turbulence was simulated with the SA-based DES model. The influence of the chordwise installation of VGs was emphatically discussed. First, the single-row VGs are, respectively, mounted at the 10, 20, and 40% chord positions, denoted as VGs1, VGs2, and VGs3. The results indicate that with the addition of the optimal configuration (VGs1), the maximum lift coefficient is extended from 1.43 to 2.44, and the stall angle of attack increases from 10° to 22° with respect to the clean airfoil. The drag coefficient of the airfoil with VGs1 is 60.8% lower than that of the airfoil without VGs at an angle of attack of 24°. On this basis, the double-row VGs’ arrangements are located at the 10 and 30% chord positions (VGs4), the 10 and 50% chord positions (VGs5) and the 10 and 70% chord positions (VGs6). Compared to single-row VGs, double-row VGs have the greater potential to suppress the flow separation. Due to the effect of VGs4, the maximum value of lift coefficient has increased to 2.61. However, the case of VGs6 degrades the overall aerodynamic performance as compared to VGs1. Further research suggest that with the increase in the height of the second row of vortex generators (VGs7), the aerodynamic characteristics of airfoil A821201 can be effectively enhanced at large angles of attack.