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建立了一种新的预报双自由度圆柱涡激振动响应的尾流振子模型,提出了以近壁点涡强度为变量描述尾流振子方程。通过势流理论推导出了结构所受流体流向和横向水动力与点涡强度的量化关系,从而得到了结构振子和流体振子的耦合方程组。使用该模型对圆柱的双自由度涡激振动问题进行了数值计算,得到了结构流向和横向的响应振幅及频率的变化规律。通过与实验结果进行对比,表明模型预测的涡激共振区、锁定频率和“8”字形运动轨迹等结果与实验观测结果基本一致。
A new wake oscillator model for predicting two-degree-of-freedom cylindrical vortex induced vibration is proposed. The wake oscillator equation is described by taking the vortex intensity near the wall as a variable. Based on the potential flow theory, the quantitative relationship between the fluid flow direction, the transverse hydrodynamic force and the point vortex strength is deduced, and the coupling equations between the structure vibrator and the fluid vibrator are obtained. The model was used to calculate the vortex-induced vibration of a two-degree-of-freedom cylinder, and the variation of the amplitude and frequency of the response was obtained. By comparing with the experimental results, it is shown that the results of the model predicted vortex-induced resonance, the locking frequency and the “8” -shaped motion trajectory are consistent with the experimental observations.