This work analyses the three-dimensional dynamic response of flexible catenary risers when subjected to the effects of an internal slug flow. The interaction between the flexible riser and the internal slug flow is a rather complex phenomenon, and this is because the forces due to the acceleration of the internal fluid influence the riser dynamics, which, in turn, influences the slug flow motion in its interior. In order to carry out this analysis, a new computational tool called SLUGFLEX has been developed, which is composed by two computational codes: the code that calculates the structural dynamic response of the flexible riser, and the other one that predicts the development of the internal slug flow. In the structural analysis, the spatial discretization of the riser is performed using spatial Euler beam finite elements, which suffer large displacements, although with small deformations. The tangent stiffness matrix and the internal force vector of the structure are calculated using the corotational approach. The internal slug flow, whose key feature is the intermittence of two different regions: a liquid slug and a large bubble of gas, is mathematically modelled by using a new one-dimensional lagrangian slug tracking method, which has been based on a model developed for straight pipes, and over which the effects of the curvature of the riser and its dynamics were added. The dynamic response of the riser is calculated by using the constant average acceleration method, in combination with the incremental iterative Newton–Raphson scheme for follower loads. The numerical results show good agreement when compared to the experimental ones obtained from the literature.

这项工作分析了柔性悬链线立管在受到内部段塞流影响时的三维动态响应。柔性立管与内部段塞流之间的相互作用是一个相当复杂的现象，这是因为内部流体加速产生的力会影响立管的动力学，进而影响其内部的段塞流运动。为了进行这种分析，开发了一种名为 SLUGFLEX 的新计算工具，它由两个计算代码组成：一个是计算柔性立管结构动力响应的代码，另一个是预测内部结构的发展。段塞流。在结构分析中，使用空间欧拉梁有限元对立管进行空间离散化，尽管变形很小，但位移很大。使用共转方法计算结构的切线刚度矩阵和内力矢量。内部段塞流的主要特征是两个不同区域的间歇性：液体段塞和大气泡，通过使用新的一维拉格朗日段塞跟踪方法对内部段塞流进行数学建模，该方法基于为直管，并在其上添加了立管曲率及其动力学的影响。立管的动态响应是通过使用恒定平均加速度方法，结合从动载荷的增量迭代 Newton-Raphson 方案来计算的。与从文献中获得的实验结果相比，数值结果显示出良好的一致性。