深海立管在参激和涡激联合作用下的模型实验及数值模拟

项目名称： 深海立管在参激和涡激联合作用下的模型实验及数值模拟

项目编号： No.51509140

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 水利工程

项目作者： 雷松

作者单位： 清华大学

项目金额： 8万元

中文摘要： 深海立管是深海油气资源开发系统的关键装备，由于所处环境恶劣，服役时间长，为确保立管的安全，出于对其强度与疲劳考虑，须对各种激励作用下的振动进行模拟。浮体升沉运动引起的立管顶张力周期性变化导致的参数激励和海流经过立管产生的泄涡是诱发立管振动及其疲劳损伤的主因。随着水深增加，海流可能引发立管的高阶模态及多模态的振动响应，且结构自身轴向和横向存在耦合效应，时变轴向参数激励的存在将使立管动态响应的预测更加困难。本项目以探索参激和涡激联合作用而导致立管的振动特性为研究目标，设计一套可以施加顶端参数激励的立管模型实验装置，在海洋工程水池展开一系列拖曳实验研究。同时，结合基于经验的尾流振子模型进行数值模拟，拟合尾流振子模型中的经验参数，通过比较立管在单纯涡激作用和参激-涡激联合作用下顺流向和横流向的振动响应，分析不同参数组合工况下参数激励对涡激振动的影响，阐明联合激励作用下深海立管动力响应的内在机制。

中文关键词： 顶张力立管；参数激励；涡激振动；动力失稳；尾流振子

英文摘要： Deepwater risers play an important role in the deep sea oil and gas resources development system. The behavior of risers subject to various excitations must be predicted in order to take strength and fatigue failures into account. This is to ensure the safety of risers in harsh environments during its long service life. Parametric excitation representing the cyclical changes of top tension in the riser caused by floater’s heave motion, as well as vortex-induced vibration (VIV) by ocean current, are the main sources of a riser’s vibration leading to fatigue damage. In deep water, the response of a riser due to VIV may be in high modes and further coupling of structure’s vibration in axial and transverse planes tends to be stronger. Hence, the axial parametric excitation that is time variant makes it more difficult to predict the dynamic response. This research is aimed at exploring the vibration characteristics of a riser subject to both parametric excitation and VIV. A number of model tests will be carried out in the towing basin using homemade but innovative experimental devices. The focus will be on developing parametric excitation devices and on VIV simulation schemes. Meanwhile, the numerical simulations based on the wake oscillator model will be applied to find the empirical parameters and fits. By compari

英文关键词： Top Tensioned Risers；Parametric Excitation；Vortex-induced Vibration；Dynamic Instability；Wake Oscillator