EI、Scopus 收录
中文核心期刊

上游静止方柱尾流对下游方柱体尾激振动效应影响

EFFECT OF WAKE INDUCED-VIBRATION RESPONSES OF A SQUARE CYLINDER BEHIND THE STATIONARY SQUARE CYLINDER

  • 摘要: 基于半隐式特征线分裂算子有限元法,对低雷诺数下串列布置上游静止方柱--下游双自由度运动方柱体结构的尾激振动问题进行了研究.首先与现有文献结果进行对比验证该方法的正确性.然后着重分析了雷诺数(Re)与折减速度(U_\rm r)两个关键参数对下游方柱尾激振动响应的影响,同时将计算结果与单方柱工况进行了对比. 数值计算结果表明,雷诺数和折减速度对下游方柱的振幅、振动频率和运动轨迹等动力响应特性的影响较大.随着雷诺数的增大,双柱系统的互扰效应从以涡激效应为主逐渐转变为尾激效应发挥主导作用,从而导致下游方柱的振动响应增强.单方柱工况结构运动轨迹均呈"8"字形. 然而,下游方柱的运动轨迹会随着雷诺数的增加而变得复杂.雷诺数较小时(Re\!=\!40, 80),下游方柱的运动轨迹基本为"8"字形. 雷诺数较大时(Re\!=\!120, 160,200), 下游方柱的运动轨迹会出现双"8"字形. 同时,下游方柱的尾流场特性主要呈现2S, 2S*, 2P, 2T, P+S和稳态6种模式.最后, 通过对流场特性进行分析,揭示了串列双方柱系统尾激振动效应的作用机理.

     

    Abstract: Wake-induced vibration (WIV) of a two-degree-of-freedom downstream square cylinder behind a stationary upstream square one are numerically investigated at low Reynolds numbers by using semi-implicit Characteristics-based split(CBS) finite element algorithm in this study. Firstly, the results are compared with the existing data in the literature to verify the accurateness of the method. Then, the influence of Reynolds number (Re) and reduced velocity (U_\rm r)on the wake-induced vibration response of the downstream square cylinder is analyzed. Meanwhile, the results are also compared with those of the single square cylinder case. The numerical results show that the Reand U_\rm rhave great influence on the dynamic response characteristics, such as amplitude, vibration frequency and motion trajectory of the downstream square cylinder. With the increasing of Re, the interaction between both cylinders changes from the vortex-induced interference to the wake one, resulting in the change of the frequency characteristics and the intensifying dynamic response of the downstream circular cylinder. The trajectories resemble figure "8" in the single square cylinder case. However, in the case of both cylinders arranged in-line, the trajectories of the downstream cylinder become complicated with the increasing of Re. The motion orbits are basically "8" figure at Re=40, 80. When the Reare 120, 160 and 200, the "dual-8" figure can be observed. Meanwhile, the wake field characteristics of the downstream square cylinder show 2S, 2S*, 2P, 2T, P+S and steady mode. Finally, the wake-induced vibration mechanisms of two square cylinders in the tandem arrangement is revealed according to the analysis of the characteristic of the flow field.

     

/

返回文章
返回