Abstract: Aimed at the issue of the flow-induced motion energy conversion system (FIMECS)－limited utilization of the energy in hard galloping branches, a new type of oscillator with a circular-triangle-attachment (Cir-Tri-Att) combined section is developed. The existing FIMECS is refitted and equipped with a torque sensor to capture fluid forces, and experimental tests are conducted on this oscillator under different excitation voltages, focusing on its flow-induced vibration and power generation capacity. Its amplitude, frequency, lift, active power, and energy conversion efficiency are discussed and analyzed. This study aims to work out a new idea for improving the power generation of the real energy conversion system and to broaden its application scope. In the vortex-induced vibration range, the oscillator captures more flow energy in the case of larger flow velocity; its vibration response shifts from soft galloping to hard galloping as its damping increases; its best branch energy conversion is in the galloping branch. In our test range, its maximum amplitude ratio is 2.43 at an excitation voltage of 3 V and a reduced velocity of 12.4. And it features a peak active power of Pharn = 24.7 W and a peak efficiency of ηharn = 25.5%, corresponding to the excitation voltage of 99 V and reduced velocity of 12.4. Compared with the triangular prism, its energy converting capability improves to a certain extent.

Key words: flow-induced motion, galloping, composite section cylinder, active power, efficiency