Abstract Buoyancy modules are essential parts in the offshore oil and gas drilling and production practices. They provide weight compensation for the riser and help avoid excessive top tension exerted by the floating platform. However, the deployment of buoyancy modules with larger diameter than the bare riser may alter the geometric shape of the riser system and greatly influence the hydrodynamic performance. Engineering designs with buoyancy modules are mostly based on experience and rigid cylinder forced vibration experimental data. Since it is difficult if not impossible to perform real sea experiments, numerical simulation becomes important in aiding the buoyancy module design and setup. In the present work, a fluid–structure interaction code based on the computational fluid dynamic model is firstly validated with the riser experimental data from MARINTEK (the Norwegian Marine Technology Research Institute) and then used to simulate the riser responses with different continuous buoyancy module setups. The Reynolds number based on the incoming velocity and the bluff body diameter ranges from 4 × 1 0 3 to 1 . 68 × 1 0 4 . The simulation results suggest that the shape alteration from the buoyancy deployment will change the vortex-induced vibration(VIV) response mode along with the vibration frequency. The cylinder fatigue damage, travelling wave response and the fluid–structure energy transfer characters are discussed under different buoyancy module setups.

中文翻译：

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不同位置浮力模块覆盖柔性圆柱涡激振动的数值研究

摘要 浮力模块是海上油气钻采实践中必不可少的部件。它们为立管提供重量补偿，并有助于避免浮动平台施加的过度顶部张力。然而，比裸立管直径更大的浮力模块的部署可能会改变立管系统的几何形状并极大地影响水动力性能。带有浮力模块的工程设计大多基于经验和刚性圆柱受迫振动实验数据。由于进行真正的海上实验很困难，如果不是不可能的话，数值模拟在辅助浮力模块的设计和设置方面变得很重要。在目前的工作中，基于计算流体动力学模型的流固耦合代码首先使用来自 MARINTEK（挪威海洋技术研究所）的立管实验数据进行验证，然后用于模拟具有不同连续浮力模块设置的立管响应。基于传入速度和钝体直径的雷诺数范围为 4 × 1 0 3 到 1 。68 × 1 0 4 。仿真结果表明，浮力部署引起的形状变化将随着振动频率的变化而改变涡激振动 (VIV) 响应模式。讨论了不同浮力模块设置下的圆柱体疲劳损伤、行波响应和流固耦合特性。