内孤立波与非均匀海流共同作用下顶张立管动力特性  

Dynamic characteristics of a top tension riser under combined internal solitary wave and non-uniform current

作　　者：蒋武杰[1] 林忠义[2] 尤云祥[1] 李巍[1] 曲衍 肖越 范模 

机构地区：[1]上海交通大学海洋工程国家重点实验室,上海200240 [2]嘉兴南洋职业技术学院,浙江嘉兴314003 [3]中海石油研究中心,北京100027

出　　处：《水动力学研究与进展（A辑）》2012年第4期424-435,共12页Chinese Journal of Hydrodynamics

基　　金：国家高技术研究和发展计划(863计划)项目(2010AA09z305);高等学校博士点基金(20110073130003)项目~~

摘　　要：基于两层流体中内孤立波的mKdV理论,采用考虑内流的弹性杆动力学方程,结合改进的Morison公式,以及考虑涡泄频率随水深变化的一个简化涡激载荷计算模型,研究了两层流体中内孤立波与非均匀海流共同作用下深海顶张立管的非线性动力响应问题。结果表明,在海流非均匀性导致的多模态涡激力作用下,深海顶张立管会发生大振幅多模态横向组合涡激共振的现象。在深海立管发生多模态组合共振的过程中,当有内孤立波作用时,不仅会使立管横向组合共振幅值显著增大,同时还会使立管在顺流向产生突发性的大变形响应。特别地,当内孤立波传播方向与海流方向一致时,立管顺流向及横向横截面弯矩与应力都会出现显著增大现象。因此,在深海立管的设计与应用中,内孤立波与海流的耦合效应是不可忽视的。Based on the mKdV theory of internal solitary waves in a two-layer fluid, a simplified formulation is used to simulate vortex-induced forces, which frequencies are permitted to vary with water depth. The dynamic responses in the transverse and longitudinal directions for a top tension riser under combined internal solitary wave and non-uniform current are considered by use of the dynamic equation of the elastic beam considering the effect of the internal flowing fluid combining with the modified Morison formula. Results show that the transversely composite resonance with the large amplitude for the riser will happen due to the multi-modally excited forces induced by such a non-uniform current. Moreover, the sudden impact loads induced by the internal solitary wave will lead to not only the remarkable increase of the transversely composite resonance amplitude, but also much complicated deflections in both transverse and longitudinal directions during the multi-modal vortex-induced vibration of the riser. In particular, the torque and stress of the cross section for the riser will remarkably increase when the propagation direction of the internal solitary wave coincides with the direction of the non-uniform current. Therefore, the influence of internal solitary waves on the dynamic characteristics of deep-sea risers can not be neglected in their designs and applications.

关 键 词：内孤立波 非均匀海流 顶张立管 多模态共振 

分 类 号：O352.2[理学—流体力学]