Linear Stability Analysis of Time-Averaged Flow Past a Cylinder
Linear Stability Analysis of Time-Averaged Flow Past a Cylinder
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经过圆柱体的时间平均流量的线性稳定性分析
DOI：
10.3970/cmes.2008.027.063
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发表时间：
2008
影响因子：
2.4
通讯作者：
S. Mittal
中科院分区：
文献类型：
--
作者：
S. Mittal
在雷诺数Re \sim 47$时，流过圆柱体的流动失去稳定性。它已被证明，在过去，线性稳定性分析（LSA）的稳态解不仅可以预测的临界Re$，但也无量纲频率，$St$，相关的不稳定性。对于较大的$Re$，非线性效应变得重要，并且稳态流的LSA不能预测正确的$St$。它示出，在一般情况下，LSA应用于时间平均流可以导致有用的信息，其稳定性。本文将这一思想应用于Re=100的圆柱绕流。时间平均流的LSA导致$St$的正确值。还使用快照方法对非定常流进行了适当的正交（POD）或Karhunen-Lo 'e}ve（K-L）分解。从这个分解的模式进行比较，使用LSA计算的不稳定模式。
Flow past a circular cylinder looses stability at a Reynolds number,$Re \sim 47$. It has been shown, in the past, that the linear stability analysis (LSA) of the steady state solution can predict not only the critical$Re$, but also the non-dimensional frequency,$St$, of the associated instability. For larger$Re$ the non-linear effects become important and the LSA of the steady-state flow does not predict the correct$St$. It is shown that, in general, the LSA applied to the time-averaged flow can result in useful information regarding its stability. This idea is applied to the$Re=100$ flow past a circular cylinder. The LSA of the time-averaged flow results in the correct value of$St$. Proper Orthogonal (POD) or Karhunen-Lo\'{e}ve (K-L) decomposition of the unsteady flow using the snapshot method is also carried out. The modes from this decomposition are compared to the unstable modes computed using the LSA.