A real-time experimental investigation of thin cambered tubercle blades for performance improvement of Darrieus vertical axis wind turbine

Darrieus vertical axis wind turbines (VAWT) have various shapes associated with them; H-shaped devices are amongst the most common designs being used. To enhance the performance of these devices, nature-inspired tubercle shapes have been implemented to these H-shaped blade profiles. Hump-back whale flippers inspire these tubercles. They have a sinusoidal pattern on the flippers, which has been stated to help these gigantic beings to have sharp turns. The present study has implemented this modification to the H-bladed profile. A NACA4412 profile has been selected for the present study. An experimental analysis has been performed with three-bladed turbines with modified shape in a subsonic wind tunnel having a straight cambered and cambered tubercle. The tubercle model outperforms the straight-cambered models. The analysis was performed at wind speeds of 6 to 7 m/s to mimic the natural wind flow operating conditions. Real-time torque data were plotted using a rotary torque sensor for 100 sec of operation. The tubercle model showed a 16.66% increase in increment in the torque value at 7 m/s.