中文摘要：

通过数值模拟和模型试验方法对一新型的 Spar 平台———多立柱式 Spar 平台的涡激运动特性进行研究。平台硬舱为四根圆柱方形阵列布置加方形中心井的形式，各柱间会产生复杂的相互干扰，不同于常规的单立柱 Spar 平台或半潜式平台，因此对其开展相应的涡激运动研究具有重要意义。研究主要关注的是不同来流角、不同流速下平台的涡激运动特性。通过涡激运动时的横荡运动、水平面内运动轨迹、首摇运动和水动力系数及绕流流场的分析，可得：在折合速度约为6-8范围内，平台横荡运动存在明显的“锁定”现象（0°来流角无侧板时“锁定”范围约为 Ur ＝7-10）。在0°来流角下较高流速时，减涡侧板对涡激运动有明显的抑制效果。平台的运动轨迹近似与平台硬舱截面的对角线平行（0°来流角除外），这不同于常规的单立柱 Spar 平台。此外，试验中还观察到较明显的首摇运动。涡激运动时各柱间绕流存在复杂的相互干扰，而在柱后形成共同的涡结构。

英文摘要：

A numerical and experimental study on the vortex-induced motions, VIM, of a new type multi-column Spar platform is presented. The hard tank of this platform consists of four circular columns arranged in a square shape surrounding the center well. Complex flow interference can happen near the columns. This special configuration is different from any kind of the existing single-column Spar platforms or Semi-submersible platforms, which indicates that it is very important and meaningful to carry out the related study on the VIM of it. The influences of different headings, velocities and the efficiency of the helical strakes have been analyzed. The main results show that the lock-in phenomenon is observed with reduced velocity between 6 up to 8 （for 0° incidence without helical strakes, the lock-in range is Ur = 7 - 11）.The helical strakes do suppress the vortex-induced motions, and have the highest efficiency for 0° incidence in a relatively high range of current velocity. The trajectories of VIM motions in the XY plane occur primarily along the cross-section diagonals （except in the 0° incidence）, which is quite different from the existing single-column Spar platforms. Relatively large yaw motion is also observed in the model test. The flow structures of vortex of the multi-columns interact strongly with each other, but the general flow pattern of the platform joints together behind it, which is similar to the single column’s pattern.