中文摘要：

由于深水浮式平台的运动幅度较固定式平台增大,其运动与下部立管的动力耦合变得更加明显。研究了上部平台运动对水下立管涡激振动的影响,基于有限元数值模拟,建立了与结构运动耦合的立管尾迹流场的涡激升力、流体阻力模型,进行了＂平台运动-立管涡激振动＂整体系统的动响应数值模拟,分析了平台横荡运动的幅值、频率等因素对水下立管涡激振动的影响。结果表明,上部平台的振动会在沿着立管展向传播的过程中被放大（称为响应放大）;与不考虑平台运动相比,立管的动响应位移增大了多倍,而且振幅放大倍数随着模态阶数的降低而增大;平台横荡振幅越大,立管振动幅值也越大,但是振幅放大倍数的变化不明显。

英文摘要：

The dynamic coupling between floating top and submarine riser becomes more remarkable due to larger fluctuation amplitude of deeper water floating platform, compared to fixed platform in shallow water. The impacts of top end motion on riser vortex-induced vibration （VIV） are explored. A coupling hydrodynamic force approach, regarding vortex-induced lift force along with fluid drag force, is developed, which essentially depends on instantaneous movement of riser. Then the dynamic characters of the integrated system including both floating top end and a riser undergoing VIV are examined by means of finite element numerical simulations. The influences of the amplitude and frequency of platform sway on riser VIV are presented. An interesting phenomenon, called nonlinear amplification, is observed that the top end vibration may be amplified as propagating from top to bottom end along riser axial span. Our numerical results indicate that riser displacement, compared to the case without top movement, becomes larger. Moreover, nonlinear amplification would get more pronounced as the number of mode order falls. However, its value would not significantly change as sway amplitude of top end increases, though the absolute amplitude of riser displacement may get larger.