深水隔水管-测试管柱系统涡激振动实验研究

在深水测试作业中，隔水管和测试管柱形成双层管柱结构，其在海流作用下发生耦合振动，存在安全隐患。为了研究海流流速对隔水管-测试管柱系统振动的影响，搭建了隔水管-测试管柱系统涡激振动的相似实验装置，开展在不同流速下隔水管-测试管柱系统涡激振动实验。实验中用应变片采集数据，用模态分析法处理实验数据，分析隔水管和测试管柱在横向和流向的应变、频率、位移标准差以及模态特征。结果表明：在海洋环境载荷作用下，隔水管与测试管柱发生接触和碰撞，导致测试管柱产生与隔水管类似的涡激振动，但隔水管的振幅明显大于测试管柱；当流速为0.5 m/s时，隔水管和测试管柱的振幅均显著增加，隔水管-测试管柱系统产生“锁定”现象；随着流速的增大，隔水管流向振动逐渐由较高频率主导，而测试管柱流向振动仍由较低频率主导。研究结果可以为深水测试作业过中隔水管振动的抑制提供参考。

Experimental research on vortex-induced vibration of deepwater riser-test string system

In deepwater test operations,the riser and the test string formed a coupling structure of doublelayered string,which caused coupling vibration under the action of ocean current,bringing about safety risks.To study the influence of ocean velocity on the vibration of the riser-test string system,a similar experimental device for the vortex-induced vibration of riser-test string system was established,and the vortex-induced vibration experiment of riser-test string system was carried out at different ocean current velocities.In the experiment,strain gauges were used to collect data,and the experimental data was processed by modal analysis method to analyze the strain,frequency,displacement standard deviation and modal characteristics of the riser and the test string in lateral and flow directions.The results showed that under the load of the marine environment,the riser and the test string contacted and collided.Consequently,the test string produced vortex-induced vibration similar to that of the riser.However,the vibration amplitude of the riser was significantly larger than that of the test string;when the ocean current velocity was 0.5 m/s,the vibration amplitude of the riser and the test string increased significantly,and the riser-test string system showed a"locks up"phenomenon;as the ocean current velocity increased,the flow direction vibration of the riser was gradually dominated by a higher frequency,but the flow direction vibration of the test string was still dominated by a lower frequency.The research results can provide a reference for the suppression of riser vibration during deepwater test operation.