Experimental analysis of the effect of pitch angle on the performance of a Darrieus vertical-axis wind turbine

¹ Laboratory of Mechanical Modeling, Energy and Materials (LM2EM), National Engineering School of Gabes, University of Gabes, Tunisia.
² higher Institute of Industrial Systems of Gabes (ISSIG), University of Gabes, Tunisia.

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The demand for sustainable energy solutions has driven increased interest in vertical-axis wind turbines (VAWTs), which offer several advantages over horizontal-axis devices. Among VAWT configurations, the Darrieus turbine remains one of the most promising concepts, yet its aerodynamic behavior is characterized by strong unsteadiness. This study presents an experimental investigation of a single-height Darrieus rotor equipped with a NACA 0018 airfoil. The rotor geometry was designed using parametric modelling and manufactured through using additive manufacturing techniques to ensure precise control of blade characteristics. A dedicated experimental test bench was constructed to measure torque and power output under controlled wind speeds conditions. The effect of blade pitch angle was examined by imposing fixed geometric angles ranging from -20° to +20°, while monitoring turbine performance. The results demonstrate a clear correlation between blade pitch and aerodynamic efficiency. The turbine achieves its optimal performance at a positive pitch angle of +20°, achieving a maximum power coefficient of Cp = 0.222 at a wind velocity of 10 m/s. These findings underline the sensitivity of Darrieus performance to geometric alignment and provide experimental evidence supporting rotor configuration optimization