On the inversion of the von Kármán street in the wake of a confined square cylinder
On the inversion of the von Kármán street in the wake of a confined square cylinder
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DOI：
10.1017/s0022112006004058
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发表时间：
2007-02
影响因子：
3.7
通讯作者：
S. Camarri;F. Giannetti
中科院分区：
文献类型：
--
作者：
S. Camarri;F. Giannetti
本文考虑了不可压缩的二维层流绕通道中对称放置的方柱的流动。在这类流动中，即使在无约束情况下，相反符号的旋涡交替地从物体喷射到尾迹中，它们相对于流动对称线的位置也会发生反转。对这一现象的物理根源进行了数值分析，并对尾迹中涡旋穿过对称线的位置进行了表征。结果表明，对于中、低堵塞比，旋涡反转的根本原因是来流中存在的涡量，并从尾迹涡度干扰的角度给出了动力学解释。通过对旋涡脱落不稳定性的线性稳定性分析，得到了进一步的认识。
This paper considers the incompressible two-dimensional laminar flow around a square cylinder symmetrically positioned in a channel. In this type of flow, even if vortices of opposite sign are alternately shed from the body into the wake as in the unconfined case, an inversion of their position with respect to the flow symmetry line takes place further downstream. A numerical analysis is carried out to investigate the physical origin of this phenomenon and to characterize the position in the wake at which the vortices cross the symmetry line. It is shown that, for low to moderate blockage ratios, the fundamental cause of the inversion of the vortices is the amount of vorticity present in the incoming flow, and a dynamic interpretation in terms of vorticity interference in the wake is given. Further insight is gained through a linear stability analysis of the vortex shedding instability.