静止圆柱尾迹的稳定性分析

采用二维非平行流的整体线性不稳定性分析和基于局部平行假设的绝对／对流不稳定性分析两种方法研究静止圆柱尾迹的稳定性，基本流场由相同的低维Ｇａｌｅｒｋｉｎ方法计算得到。结果证实，随着Ｒｅ数的增加直至Ｋａｒｍａｎ涡街形成，先后发生了两次整体模太的跳跃和一次Ｈｏｐｒ分叉，并首次用绝对／对流不稳定性理论解释了这一现象。

Stability Analyses of Wakes Behind a Stationary Circular Cylinder

In this paper two approaches, including global instability analysis of the entire two dimensional nonparallel flow and local absolute/convective instability analysis of assumed parallel flows, are used to investigate the stability characteristics of wake flows behind a stationary circular cylinder. The basic flows are computed by a low-dimensional Galerkin method. The results confirm that twice global mode switching and a Hopf bifurcation occur with increasing Reynolds number Re up to which the Karman vortex street forms, and the first explanation of this phenomenon with absolute/convective instability theory is given.