On the quasiperiodic state in a moderate aspect ratio Taylor–Couette flow
On the quasiperiodic state in a moderate aspect ratio Taylor–Couette flow
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DOI：
10.1063/1.3407665
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发表时间：
2010-04
影响因子：
4.6
通讯作者：
Eboshogwe Imomoh;J. Dusting;S. Balabani
中科院分区：
文献类型：
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作者：
Eboshogwe Imomoh;J. Dusting;S. Balabani
利用时间分辨粒子图像测速技术，研究了长径比 γ=11.2、半径比 η=0.81、仅内筒旋转的泰勒-库埃特容器中导致混沌流的过渡路径。使用空间分辨频谱分析来识别迄今为止未报告的转变序列，通过该序列，流动从波状涡流变为高调制频率的准周期状态。使用适当的正交分解详细描述了调制波状涡流的性质，通过它揭示了调制类似于快速移动方位角波（FMAW）。与之前以高得多的纵横比观察到的 FMAW 相比，该模式直接出现在波状涡流之后，并且作为 CVF 状态的前兆。 FMAW 还与每个泰勒涡核上的同向涡度波动相关，其强度在靠近端壁处减弱。
The transition pathway leading to chaotic flow in a Taylor–Couette vessel of aspect ratio γ=11.2 and radius ratio η=0.81 with only the inner cylinder rotating has been studied using time-resolved particle image velocimetry. A hitherto unreported sequence of transitions, whereby the flow changes from wavy vortex flow to a quasiperiodic state of high modulation frequency, is identified using spatially resolved spectral analysis. The nature of the modulated wavy vortex flow is detailed using proper orthogonal decomposition, through which it is revealed that the modulation is similar to a fast moving azimuthal wave (FMAW). In contrast with previous observations of the FMAW at a much higher aspect ratio, the mode appears directly after wavy vortex flow and as a precursor to the CVF regime. The FMAW is also associated with codirectional vorticity fluctuations on each Taylor vortex core that diminish in strength close to the endwalls.