为了研究不同系泊条件下小质量比结构的涡激振动响应规律,本文对质量比为0.422、长细比为7的浮力筒开展了不同系缆绳长度和顶端距水面距离工况下的模型试验,并对其运动轨迹、幅值、频率等参数进行了对比和研究,发现:小质量比与细长比浮力筒的振动频率随约化速度的增大而几乎线性增大,仅在很小的范围"锁定"于固有频率,且横向振幅始终较大,未出现下端分支.实验过程中观察到了明显的艏摇现象,通过对浮力筒艏摇运动特性的研究,发现当约化速度较小时,艏摇运动比较杂乱,其中有一个较大的频率分量与横向振动主频率相等.同时,横向振动也有一个较为明显的频率分量与艏摇运动的主频率相等.当约化速度大于6.5以后,艏摇运动与横向振动都趋于稳定,仅有一个主要频率,且两者频率相等,证实了艏摇运动是由浮力筒两侧漩涡交替脱落形成的压力差引起的.%To investigate the response of vortex-induced motion of structures with low mass ratio under various mooring conditions, an experiment was conducted on a buoyancy can with m* =0.422, and L/D =7 under the conditions of different lengths of mooring line and different distances from top to water surface.The responses of trajectory, ampli-tude, frequency, and other parameters were analyzed in detail.The results showed that the vibration frequency of the cylinder with a small mass ratio and slenderness ratio increased nearly linearly with the rise of reduced velocity.Fur-thermore, the cylinder was"locked"at the natural frequency only in a very small range, the lateral amplitude was al-ways large, and the lower branch failed to appear.In addition, during the experiment, an obvious yaw was observed and the yaw characteristics were investigated.The yaw motion was in disorder when the reduction speed was small and a larger frequency component was equal to the lateral vibratory main frequency.In addition, one of the apparent lateral vibratory components was equal to the main frequency of the yaw motion.When the reduction speed was larger than 6.5, both the yaw motion and the lateral vibration tended to stabilize and only one main frequency existed.In addition, both frequencies were equal, and these results verified that the yaw motion was due to the pressure differ-ence formed as a result of the alternate falling off of the vortex on both sides of the buoyancy can.
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