Effects of CFJ flow control on aerodynamic performance of symmetric NACA airfoils
Abdolamir Bak Khoshnevis, Shima Yazdani, Erfan Salimipour
Abstract
This paper investigates the effects of co-flow jet on the aerodynamic performance of some symmetric blade sections of wind turbines. The Reynolds number of 1.3 × 105, angles of attack between 0° and 18° and momentum coefficients of 0.03, 0.05, and 0.08 are considered for four airfoils of NACA 0012, 0015, 0018, and 0021 as the blade sections. To numerically simulate the fluid flow, the Navier-Stokes equations are solved with a transitional turbulence model. The aerodynamic coefficients along with the lift to drag ratio are calculated and the results are compared with together for the baseline and co-flow jet geometries. The results of the baseline airfoils show that the NACA 0012 and NACA 0015 airfoils generate a larger lift at small angles of attack where the NACA 0018 and NACA 0021 airfoils produce a higher lift at larger angles of attack. Furthermore, the obtained results reveal that applying the co-flow jet has a positive effect on delaying the stall angle and increasing the lift coefficient. The aerodynamic coefficients are also more improved by increasing the thickness once the appropriate momentum coefficient is applied. The results also indicate that the momentum coefficient of 0.05 is sufficient for most of the cases.