关于卡门涡街形状稳定性的一点分析

An analysis of the stability of Karman vortex street configurations

在圆柱绕流的卡门涡街中,单个涡对于来流有相对速度,以该速度观察,其周围的流线更类似无旋理论中有环量的圆柱绕流。因此在势流解的基础上,运用扰动理论分析了涡街形状的稳定性问题。结果表明,涡位置的纵横比有一变化范围,以卡门的经典值为下限,与涡相对速度,实际涡核的大小及其环量都有关系,但与Re不构成单调的关系。与实验数据和数值模拟的结果进行对比,表明论文的分析是合理的。

Vortices in the Karman vortex street move relatively to the uniform flow. The relative stream line pattern about each vortex is similar to the flow around a circular cylinder with circulation. Based on complex potential solution of moving cylinders with circulation, the stability of Karman vortex street configurations is analyzed with perturbation theory in this paper. The result shows that the spacing ratio for vortex street varies within certain range but with the lowest limit 0.281 by Karman＇s result, and it is affected by its relative speed, actual size and circulation. Comparison was made between experimental results and the calculations from numerical simulation with finite element method. It shows that analvsis herein is reasonable_