雷诺数对于方柱流致振动能量收集系统的影响

Under the action of incoming flow, the square cylinder can generate more intense vibration responses than the circular cylinder, which is beneficial for energy harvesting. Numerical simulations for FIV of the square-cylinder energy conversion system are carried out. URANS equations are used in conjunction with the shear stress transport k-ω turbulence model to predict the flow, and the equations for vibrations are solved by the Newmark-β algorithm. The present numerical method is validated against the published data with good consistency. The Reduced velocity U_r is varied from 1-20, with corresponding Reynolds numbers of 24 000-160 000. The numerical results indicate that the Reynolds number significantly affects the frequency response, amplitude response, vortex shedding mode, and energy conversion efficiency. The highest efficiency point locates at Re=88 000, with a value of 7.156%. When Re>120 000, the system transits from vortex-induced vibration into galloping, and its vibration responses as well as energy harvesting characteristics change sharply. Fully developed galloping motion occurs when Re>144 000.