Experimental study on flexible and rigid 3D-Printed Savonius vertical axis wind turbines with aerodynamic augmentation

Savonius vertical axis wind turbines (SVAWTs) are promising for low-wind and urban environments due to their simple design and minimal noise. This study investigates two-bladed SVAWTs 3D-printed with flexible and rigid blade materials, tested in wind speeds of 8–18 m/s, with and without an aerodynamic augmentation shell (AAS). Key aerodynamic and electrical parameters, including velocities, angular speed, voltage, and power output, were measured under varying loads. Results show that the AAS consistently enhances performance by reducing cut-in speeds and increasing rotational velocity, voltage, and electrical power. Flexible blades improve angular speed and power at moderate wind speeds, while rigid blades exhibit higher torque and stronger aerodynamic deceleration. Across all configurations, the AAS significantly boosts efficiency, with peak power coefficient improvements up to 147% at 15 m/s. These findings highlight aerodynamic augmentation and material flexibility as effective strategies to improve small-scale SVAWT performance for urban and distributed renewable energy applications.