Numerical Investigation of the Effect of Airfoil Camber on the Aerodynamic Performance of Small-Scale Horizontal Axis Wind Turbines

The aerodynamic performance of wind turbine rotors strongly depends on the characteristics of the selected airfoil profile and rotor configuration, particularly under low Reynolds number conditions typical of small-scale wind energy systems. In this study, the influence of airfoil camber and blade number on the aerodynamic performance of a horizontal axis wind turbine (HAWT) was investigated. Three airfoil profiles belonging to the NACA four-digit series, namely NACA 2412, NACA 4412, and NACA 6412, were analyzed using the QBlade software, which combines the XFOIL solver for airfoil analysis with the BEM method for rotor performance prediction. The aerodynamic characteristics of the airfoils were first evaluated in terms of lift coefficient (CL), drag coefficient (CD), and lift-to-drag ratio (CL/CD) over a Reynolds number range of 8×10⁴–2.5×10⁵, representing low wind speed conditions typical of regions such as Eastern Anatolia. Subsequently, rotor performance was investigated for two-, three-, and four-bladed configurations using power coefficient (Cₚ) and thrust coefficient (Ct) analyses. The results indicate that increasing airfoil camber enhances lift generation and aerodynamic efficiency. Among the investigated profiles, NACA 6412 achieved the highest Cₚ values, indicating improved energy extraction capability. However, this airfoil also generated higher thrust loads. Considering both power coefficient and thrust coefficient together, the NACA 4412 airfoil provided the most balanced aerodynamic performance. The results demonstrate that moderate camber airfoils can offer an effective compromise between energy production and aerodynamic loading for small-scale wind turbines operating under low Reynolds number conditions.