【作者】 王国兴；

【导师】 李华军；

【作者基本信息】 中国海洋大学 ， 港口、海岸及近海工程， 2006， 博士

【摘要】 海底管线是海洋油气集输与储运系统的重要组成部分,被喻为海上油气田的“生命线”,在海洋油气资源的开发利用中发挥着重大作用,海底管线的安全正常运行是海上油气田安全生产的重要保证。海底管线管跨结构由于具有特殊的结构形式,在海流作用下会发生复杂的涡致振动以及频率“锁定”现象,并诱发流体与结构之间的相互作用,由此导致的结构失稳以及疲劳破坏是海底管线损伤的重要形式。针对海底管线管跨结构的涡致耦合振动问题,考虑到二维流场数值模拟的局限性以及管跨结构的动态响应具有轴向分布的特点,本文基于二维的标准k ?ε湍流模式,以及考虑管内流体流动影响的管跨结构运动控制方程,构建了由水动力模块和结构动力模块两部分构成的准三维数值模型,用于描述海底管线管跨结构的涡致振动以及涡致振动过程中流体与结构之间的相互作用。该模型的本质是用二维模型求解三维问题,其基本思想很大程度上体现在它的数值求解过程中。为了解决流固耦合数值研究中两相介质界面上力与运动关系的传递与协调问题,本文在总结前人研究工作的基础上,提出了一种新的动态块结构数值网格生成技术,该技术将包含壁面运动边界的网格块的运动与块内网格的变形结合起来,共同承担因壁面边界运动引起的域内网格的变形,因此能够满足结构大幅运动的需要,而不引起网格的畸变。本文发展的准三维数值模型与新的动态块结构数值网格技术相结合,被成功应用于海底管线管跨结构涡致耦合振动问题的研究。通过数值算例,深入研究了涡致耦合振动过程中管跨结构的动态响应和动力特性以及绕流流场的水动力特性,详细分析了涡致耦合振动的各种影响因素,探讨了频率“锁定”以及流固耦合等非线性动力特性和行为,并得出了相关的结论。为了深化对该涡致耦合动力更多还原

【Abstract】 As an important component of the offshore oil and gas storage and transportation system, submarine pipelines are playing the significant roles in the offshore exploitation. They are called as the lifeline of the offshore oil and gas fields. The security production of the offshore oil and gas fields depends largely on the safe operation of the submarine pipelines. Due to the special structural style, the vortex-induced vibrations (VIV), the‘lock-in’phenomenon and the fluid-structure interaction (FSI) of the submarine free-span pipelines can occur when they exposed to the ocean current. The complicated hydrodynamic behavior is apt to result in the loss of the structural stability and the fatigue damage.The two-dimensional numerical simulation is limited in this research because the structural responses of the submarine free-span pipelines are distributed axially. Based on the two-dimensional standard k ?εturbulence model in conjunction with the structural governing equations, a quasi three-dimensional numerical model incorporating the hydrodynamics module and the structural dynamics module is developed in this dissertation to depict the VIV and the FSI of the submarine free-span pipelines accurately. The essence of the presented numerical model is to solve a three- dimensional problem by using a set of two-dimensional numerical simulations. To deal with the grid movement induced by the structural vibration in the numerical simulation of the FSI problem, a new generation method of the dynamic block- structured grid based on the previous researchers’work is proposed in this dissertation. In this method, the movement of the grid block around the moving structural boundary is combined with the regeneration of the inner-block grid to avoid the aberrance of the grid.The proposed quasi three-dimensional numerical model in conjunction with the dynamic block-structured grid generation method is applied successfully in the studies on the VIV and FSI problem of the submarine free-span pipelines. The structural responses and dynamical characteristics are analyzed in detail by numerical approach. Based on the flow visualization, the hydrodynamics of the flow field including the flow separation, the vortex shedding and the wake pattern are discussed. The nonlinear更多还原