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中文核心期刊

卡门涡街的慢不稳定性

ON THE SLOW INSTABILITY OFKARMAN VORTEX STREET

  • 摘要: 经典的卡门涡街点涡模型只在一孤立情况下是线性稳定的.数值计算还表明这一特性对该流动的其它更复杂的模型仍然成立.本文引进慢不稳定性概念,对卡门涡街的稳定性问题进行了比较全面和细致的数值研究.首先用点涡模型,做数值模拟,证实了早年卡门的线性稳定性分析结果,数值模拟卡门涡街的非线性稳定性却表明,卡门涡街对有限大小的扰动,表现出慢不稳定现象.然后用伪谱方法对涡街的形成进行了直接数值模拟,进一步证实卡门涡街的这种慢不稳定性.

     

    Abstract: The KarmAn vortex street being linearly stable for an isolated case according to it’s classical point-vortex model has been shown numerically to hold also for other more complicated models. The stability of the Karman vortex street verified by using point-vortex model when perturbed infinitesimally is however a “slow instability”as shown by the simulation when the street is to be perturbed by finite disturbances.The concept of“slow instability” was verified to exist also in the case of wake flow by using th...

     

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