This paper presents a comprehensive numerical investigation of the undamped, simultaneous in-line, and transverse flow-induced vibrations of two identical diamond cylinders (of cross-stream length $D$) in a tandem arrangement at a low Reynolds number (= 100) in uniform flow, using a stabilized space–time finite-element formulation. The study focuses on the effects of cylinder proximity and shape, considering diamond cylinders with a mass ratio of 10 and a separation distance of 5$D$ and varying the reduced velocity from 1 to 20. The results reveal distinct lock-in behavior for the upstream and downstream cylinders, with a low-frequency extended lock-in phenomenon observed for the downstream cylinder. The motion trajectories of both cylinders exhibit a distinctive “raindrop-shaped” pattern. Notably, the synchronization zone shows a non-zero mean lift for a narrow range of reduced velocity. The study also identifies three distinct modes of vortex arrangement in the gap region between the cylinders. Comparing the findings for tandem diamond cylinders with those for single diamond and tandem square cylinders provides further evidence of the significant impact of proximity and shape on the vibration characteristics of the cylinders.

本文对两个相同的金刚石圆柱体（横流长度$丁$) 在低雷诺数 (= 100) 的均匀流动中串联排列，使用稳定的时空有限元公式。该研究侧重于圆柱体接近度和形状的影响，考虑质量比为 10 且分离距离为 5 的金刚石圆柱体$丁$并将降低的速度从 1 变为 20。结果揭示了上游和下游气缸的不同锁定行为，下游气缸观察到低频扩展锁定现象。两个圆柱体的运动轨迹都呈现出独特的“雨滴形”模式。值得注意的是，同步区显示了一个窄范围的减速的非零平均升力。该研究还确定了圆柱体之间间隙区域中三种不同的涡流排列模式。将串联金刚石圆柱体与单菱形和串联方形圆柱体的发现进行比较，进一步证明了接近度和形状对圆柱体振动特性的显着影响。