【摘要】 基于海流能发电涡激振动驱动俘获能量这一想法,对耦合连接的四圆柱结构在均匀海流流速下的自由涡激振动进行模拟发现:振动结构的响应幅值在较大和较小约化速度下,随组合间距比LH/D~2的变化相差较大。因此对U_r=5.71和U_r=14.29两种约化速度下结构位移幅值谱图、升力特性、相位差进行分析,结果表明:U_r=5.71时,不同间距比下各圆柱升力与位移间的相位角Φ不同,存在明显的主频且按较规则的正弦规律变化,四个圆柱对结构的振动都起激励作用,各圆柱俘获的水动能或转移到水流中的机械能相对稳定;而U_r=14.29时,各圆柱升力波动不规则,升力频率成分复杂,升力位移间的相位角Φ不明显,各圆柱俘获水动能不稳定,对结构振动起主要作用的是下游两圆柱。分析结果对柱群结构俘获海流能时其约化速度范围的确定有参考价值。更多还原

【Abstract】 Based on hydrokinetic energy harvested in ocean current power generation driven by vortex-induced vibration(VIV), the free VIV of a four cylindrical structure with coupling connection under uniform current velocities was simulated. It was found that the response amplitudes of the vibration system were significantly different under smaller and larger reduced velocities U_r with the change of combination spacing ratio LH/D~2. Therefore, amplitude spectra of displacement, lift characteristics, phase angles of the structure under U_r=5.71 and U_r=14.29 were analyzed. The results show that when U_r=5.71, lift forces change along sine signal and the main frequencies of each cylinder’s lift force are obvious under different spacing ratios, the phase angles Φ between lift force and displacement are different, four cylinders all have incentive effect on the vibration of the structure, consequently, the harvesting hydrokinetic energy from current or the mechanical energy transferred to current are stable; when U_r=14.29, the lift forces of each cylinder fluctuate irregularly, frequency components are complicated, the phase angles Φ between the lift force and displacement are not obvious, so the harvesting hydrokinetic energy of each cylinder is not stable and the two cylinders in downstream play an important role in structure vibration. The study results provid a reference to the reduced velocity range for a multi-cylinder structure when energy is extracted from ocean current.更多还原