内孤立波作用下顶部张紧式立管动力特性

Dynamic response of the top tension riser in internal solitary waves

基于内孤立波mKdV理论,采用考虑内流的细长杆动力学方程,结合改进的Morison公式,研究两层流体中内孤立波与顶张立管的相互作用问题。针对东沙群岛南部海域附近某实测内孤立波特征参数,计算分析在该内孤立波作用下某顶张立管的内孤立波载荷与运动响应,以及立管横截面弯矩及其应力的变化特性。研究表明,内孤立波不仅会对顶张立管产生突发性的冲击载荷以及大幅度水平变形,而且还会使其横截面弯矩及其应力显著增大。因此在深海立管的设计与应用中,内孤立波的影响是不可忽视的。

Based on the mKdV theory of internal solitary waves in a two-layer fluid,a theoretical model for analyzing the interaction of internal solitary waves with the top tension risers is presented by use of the riser dynamic equation based on the slender beam theory considering the effect of the internal flowing fluid combining with the modified Morison formula.The observational data near the Dongsha Island are used as the characteristic parameters of internal solitary waves,the characteristics of the hydrodynamic load and dynamic response as well as the torque and stress of the cross section for the riser due to such an internal solitary wave are computed and analyzed.Results show that internal solitary waves will give rise to sudden impact load and large deformation,as well as remarkable torque and stress of the cross section for the riser.Therefore,the influence of internal solitary waves on the dynamic behaviours of deep-sea risers can not be neglected in their designs and applications.