中文摘要：

海洋钻井立管系统作为连接水下井口和海上浮式钻井平台的重要通道,在一定雷诺数范围内,流体流过立管会发生旋涡生成和脱落现象,使立管在横流向和顺流向产生周期性涡激振动,加剧立管振动和管内钻柱与水下井口设备的碰撞,使立管成为油气开发中最易损坏的设备之一。为解决上述问题,选取浮式钻井平台系统中的单圆柱立管作为研究对象,在层流状态的不同雷诺数条件下对立管尾流旋涡变化过程和不同约化速度条件下的涡激振动规律进行仿真,结果表明,随着雷诺数的增加,旋涡在立管表面脱落频率加快,单个旋涡形态变大和瞬时涡量强度增加。随着约化速度的增加,流场中脱落的旋涡半径减小,立管振动对旋涡产生的影响逐渐增加,当约化速度进一步变大时,单圆柱立管脱离锁振区间,振动程度会减弱。为海洋钻井立管系统优化设计提供了依据。

英文摘要：

The offshore drilling riser system as an important channel connects the subsea wellhead and the off- shore floating drilling platform. In a certain range of Reynolds number, vortex formation and shedding phenomenon occur when the fluid flows through the riser, which makes the riser produce periodic vortex - induced vibration in cross flow and smooth flow, intensifies the riser vibration and the collision of snhsea wellhead equipment and the drill string, and causes the riser become the equipment most easy to damage in the oil and gas development. In the paper, we selected a single cylindrical riser of floating drilling platform system as the research object, and simulated the change process of riser wake vortex and the condition of vortex - induced vibration regularity under different reduced speeds. We found that with Reynolds number increasing, the vortex shedding frequency becomes faster in the riser surface, the single vortex form becomes larger and instantaneous vorticity intensity increases. With the increase of re- duced speed, the radius of vortex shedding decreases in the flow field, the riser vibration increases radually with the impact of vortex produce. When the reduced rate is further increased, the single cylindrical riser break away from the lock -up range, then the vibration level will diminish.