The effect of pitch angle on blade loading and in-rotor wake dynamics in an H-type vertical axis wind turbine

• Validates simplified 2D numerical simulations with experimental results, providing a tool for engineering design. • Investigates how varying blade pitch angles affect aerodynamic loading in an H-type vertical axis wind turbine. • Identifies pitch-induced changes in blade-wake interactions and in-rotor flow dynamics in relation to the overall performance of the turbine This study investigates the influence of blade pitch angle on blade loading and flow dynamics in a three-straight-bladed vertical axis wind turbine. A detailed characterization of the rotor was performed to analyze blade loads, pressure distributions, rotor fluid dynamics, and blade–wake interactions as functions of azimuthal angle and effective angle of attack, across various preset pitch angles. A two-dimensional computational fluid dynamics model was employed to simulate a vertical axis wind turbine with NACA 0015 blade profiles, a rotor diameter of 0.750 m, and a chord-to-diameter ratio of 0.16. Blade pitch angles from 8 ∘ toe-in to 6 ∘ toe-out were tested at a fixed Reynolds number of 5 × 10 5 . The results show that toe-out configurations delay the formation and shedding of the leading-edge vortex, enhancing aerodynamic performance. For instance, adjusting the pitch angle from 0 ∘ to 2 ∘ toe-out led to a significant increase (over 12%) in power output. In contrast, toe-in pitch angles tend to induce early leading edge vortex formation and rapid detachment, resulting in increased drag and reduced torque generation. Additionally, for certain configurations, toe-out angles helped mitigate the formation of trailing-edge vortices that can counteract leading edge vortex induced lift. Overall, the validated computational approach provides valuable insights into rotor behaviour and can inform blade design and control strategies to optimize turbine performance under varying operational conditions, with a reduced cost, becoming a real engineering design tool.