Q Blade-Based Simulation of a 7° Tapered Wind Turbine Blade Employing NACA 4412 Airfoil for Aerodynamic Performance Evaluation

The aerodynamic behavior of small-scale wind turbines is primarily influenced by blade geometry and airfoil selection. This study investigates the aerodynamic performance of a four-bladed horizontal-axis wind turbine (HAWT) using the NACA 4412 airfoil through numerical simulation in Q Blade software. The rotor features a tapered blade with a radius of 0.3 m and a pitch angle of 7°, operating at an average wind velocity of 3.6 m/s. Simulations were conducted based on Blade Element Momentum (BEM) theory to analyze variations in lift coefficient (Cl), drag coefficient (Cd), moment coefficient (Cm), and power coefficient (Cp) over different angles of attack and rotational conditions. The results show that the NACA 4412 airfoil exhibits favorable aerodynamic characteristics at moderate angles of attack, with a maximum lift coefficient of approximately 1.6 and a peak lift-to-drag ratio (Cl/Cd) of around 120 at α ≈ 8°. Pressure distribution analysis indicates minimal flow separation and stable suction behavior along the upper surface, contributing to efficient lift generation. The variation of Cl and Cd over a full rotational cycle reveals periodic but smooth aerodynamic loading, suggesting stable performance and low drag fluctuation. Overall, the airfoil demonstrates high aerodynamic stability and efficiency, confirming its suitability for low-speed small-scale wind turbine applications.