Abstract Flow-induced vibrations (FIV) of the cylinder with an upstream wake interference is rather different and more complex comparing with vortex-induced vibrations (VIV) of an isolated cylinder in the uniform flow, due to the wake interference mechanism involved. In this study, the forced vibration experiment is carried out on a rigid cylinder placed in tandem downstream of a stationary cylinder. The hydrodynamic coefficients of the forced vibrating cylinder, involving the steady drag coefficient C d , the excitation coefficient C l v and the added mass coefficient C m y , are obtained for the gap ratio G / d = 2–8 (where G is the streamwise distance between the centers of two cylinders and d is the cylinder diameter). Compared with an isolated cylinder, the mean drag coefficient is dramatically reduced, and a much broader positive C l v that extends to higher amplitude and lower reduced frequency is observed, the negative added mass coefficient presents for lower reduced frequency, for the cylinder with an upstream wake interference. A significant change in the distribution of hydrodynamic coefficients is found during the flow interference mode converting from the proximity interference into the full wake interference. By means of discrete vortex method (DVM) simulations, the free dynamic response of an elastically mounted cylinder placed in the wake of a stationary cylinder is numerically simulated. Comparison between the free and forced vibration of the downstream cylinder shows a good agreement between the superposed free-vibration response plot and the contour line of zero C l v . This result confirms the correlation between free and forced vibration for the cylinder FIV response with an upstream wake interference, and further suggests that the forced vibration can be one approach to predicting the dynamic response and mapping the hydrodynamic properties of the FIV of multiple interfering cylinders.

中文翻译：

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具有上游尾流干扰的横流振荡圆柱体的动力响应和水动力系数

摘要 由于涉及尾流干扰机制，与均匀流动中孤立圆柱体的涡激振动（VIV）相比，具有上游尾流干扰的圆柱体的流激振动（FIV）是相当不同和更复杂的。在这项研究中，强迫振动实验是在一个刚性圆柱体上进行的，该刚性圆柱体串联在一个固定圆柱体的下游。对于间隙比 G / d = 2–8（其中 G 是流向距离），可以得到受迫振动筒的流体动力系数，包括稳态阻力系数 C d 、激振系数 C lv 和附加质量系数 C my 。两个圆柱体的中心之间，d 是圆柱体直径）。与孤立圆柱体相比，平均阻力系数显着降低，并且观察到更广泛的正 C lv 延伸到更高的振幅和更低的降低频率，负增加的质量系数呈现为更低的降低频率，对于具有上游尾流干扰的汽缸。在流动干扰模式从邻近干扰转换为全尾流干扰的过程中，水动力系数的分布发生了显着变化。通过离散涡流法 (DVM) 模拟，对放置在静止圆柱体尾流中的弹性安装圆柱体的自由动态响应进行了数值模拟。下游圆柱体的自由振动和受迫振动之间的比较显示叠加的自由振动响应图与零 C lv 等高线之间具有良好的一致性。