Numerical simulations of the Vortex-Induced Vibration (VIV) about a large-scale flexible pipe subject to shear flow were carried out in this paper. Efficiency verification was performed firstly, validating that the proposed fluid–structure interaction solution strategy is competent in predicting the VIV response. Then, the VIV characteristics related to multi-mode and spanwise hybrid waveform about the flexible pipe attributed to shear flow were investigated. When inflow velocity rises, higher vibration modes are apt to be excited, and the spanwise waveform easily convertes from a standing-wave-dominated status to a hybrid standing–traveling wave status. The multi-mode or even multiple-dominant-mode is prone to occur, that is, the dominant mode is often followed by several apparent subordinate modes with considerable vibration energy. Hence, the shedding frequencies no longer obey Strouhal law, and vibration trajectories become intricate. According to the motion analysis concerning the coupled cross-flow and in-line vibrations, as well as the corresponding wake patterns, a tight coupling interaction exists between the structural deformation and the wake flow behind the flexible pipe. In addition, the evolution of the vortex tube along the pipe span and a strong 3D effect are observed due to the slenderness of the flexible pipe and the variability of the vortex shedding attributed to the shear flow.

本文对大型柔性管在剪切流作用下的涡激振动（VIV）进行了数值模拟。首先进行了效率验证，验证了所提出的流固耦合解决方案策略能够胜任VIV响应的预测。然后，研究了与剪切流引起的挠性管的多模态和翼展方向混合波形有关的VIV特性。当流入速度上升时，会激发更高的振动模式，并且展向波形很容易从驻波为主的状态转换为混合驻波状态。多模或什至多支模很容易发生，也就是说，支模通常跟随着具有明显振动能量的几个明显的从属模。因此，脱落频率不再服从斯特劳哈尔定律，并且振动轨迹变得复杂。根据有关横流和管道内耦合振动的运动分析以及相应的尾流模式，在挠性管后面的结构变形和尾流之间存在紧密的耦合作用。此外，涡流管沿管径的演变以及强3由于挠性管的细长和剪切流引起的涡旋脱落的变化，观察到了D效应。