A numerical study based on the wake oscillator model has been conducted to determine the vortex-induced vibration (VIV) responses of a flexible riser with an axial time-varying tension. Three different types of flows, viz., linear shear, exponential shear, and real stepped flows, have been considered. The coupling equations of a structural oscillator and a wake oscillator have been solved using a standard central finite difference method of the second order. The VIV response characteristics including the structural displacement, structural frequency, displacement envelope, and displacement evolution for three different flow profiles have been systematically compared. Subsequently, for each flow profile, the effect of the different tension models on the VIV characteristics has been investigated. The numerical results indicated that, both the VIV displacement and VIV frequency in real stepped flow had diverse characteristics from those in linear shear flow. Compared with the corresponding VIV characteristics in real stepped flow, the VIV displacement in exponential shear flow was similar, however, the VIV frequency in exponential shear flow was disparate. The VIV displacement with the constant tension model had larger values than that with the real tension model.

已经进行了基于尾流振荡器模型的数值研究，以确定具有轴向时变张力的柔性立管的涡激振动（VIV）响应。已经考虑了三种不同类型的流动，即线性剪切、指数剪切和实际阶梯式流动。结构振子和尾流振子的耦合方程已使用二阶标准中心有限差分法求解。系统比较了三种不同流动剖面的VIV响应特性，包括结构位移、结构频率、位移包络线和位移演化。随后，对于每个流动剖面，研究了不同张力模型对 VIV 特性的影响。数值结果表明，实际阶梯流中的VIV位移和VIV频率都具有与线性剪切流不同的特征。与实际阶梯流中相应的VIV特性相比，指数剪切流中的VIV位移相似，但指数剪切流中的VIV频率不同。恒张力模型的VIV位移值大于真实张力模型的VIV位移值。