Effect of angle of attack on flow-induced vibration characteristics and power generation of cantilevered prisms for FIV power generation system

Abstract

To develop the power generation system using iron-gallium alloy, we focus on the transverse low-speed galloping vibration for a D-section prism and a rectangular prism with a critical depth section of less than the side ratio D/H ≈ 0.6 (where D is the depth of the prism in the flow direction and H is the height of a prism normal to the flow direction) which vibrates at a reduced velocity Vr lower than the resonant velocity. The free vibration test using a plate spring was carried out in the water tunnel to investigate the effects of the angle of attack and the vibration direction on the vibration characteristics. The vibration direction I of the prism is the same as the longitudinal direction of the prism. The vibration direction II of the prism is the same as the transverse direction to flow. The power generation experiment using the iron-gallium alloy also was carried out to investigate the effects of angle of attack on the energy harvesting. The D-section prism with the side ratio of D/H = 0.23 for the vibration direction I vibrates at a wide range of angle of attack in comparison with the other prisms. The maximum electric power using a D-section prism with D/H = 0.23 is 26 mW at Vr = 3.56.

Keywords

• flow-inducrd vibration
• low-speed galloping
• rectangular prism
• d-section prism
• angle of attack
• vibration-powered generation
• energy harvesting