Abstract
The flow characteristics of a new hybrid vertical axis wind turbine which has advantages of the drag type and the lift type wind turbine have been investigated by the conditional sampling PIV. The experimental apparatus is constructed using the PIV measurement system with a conditional sampling device and a new hybrid vertical axis wind turbine model installed in a circulating water channel. The measured velocity vector fields have clarified that the low velocity regions are inside of rotating turbine and the downstream of it. The influences of the low velocity regions on the torque generated by the blades are investigated by the tangential forces calculated by the pressure distribution around the blades calculated from the velocity fields measured by PIV. And, it has been clarified that the tangential forces of the blades in the low velocity regions are small. Moreover, it has been clarified that the tangential forces generated by the rotating hybrid blades are sourced not only by the lift but also by the drag in the low tip speed ratio case. Therefore, the effectiveness of the hybrid blade for the new vertical axis wind turbine has been demonstrated.
