Criteria Of Turbulent Transition In Parallel Flows
Criteria Of Turbulent Transition In Parallel Flows
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DOI：
10.1142/s0217984910023815
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发表时间：
2009-06
期刊：
影响因子：
--
通讯作者：
H. Dou;B. Khoo
中科院分区：
文献类型：
--
作者：
H. Dou;B. Khoo
基于能量梯度法，分别提出了压力驱动流和剪切驱动流的湍流转捩判据。对于压力驱动流，湍流转捩的充分必要条件是平均流中存在速度拐点。对于剪切驱动流，湍流转捩的充分必要条件是平均流剖面中存在零速度梯度。结果表明，湍流转捩可以通过能量梯度函数的奇异性来实现，这种奇异性可能与动力系统中的混沌吸引子有关。扰动在过渡中的作用也阐明了导致能量梯度函数接近奇点。最后，令人感兴趣的是，可以通过调制能量梯度函数的分布来控制湍流。
Based on the energy gradient method, criteria for turbulent transition are proposed for pressure driven flow and shear driven flow, respectively. For pressure driven flow, the necessary and sufficient condition for turbulent transition is the presence of the velocity inflection point in the averaged flow. For shear driven flow, the necessary and sufficient condition for turbulent transition is the existence of zero velocity gradient in the averaged flow profile. It is shown that turbulent transition can be effected via a singularity of the energy gradient function which may be associated with the chaotic attractor in dynamic system. The role of disturbance in the transition is also clarified in causing the energy gradient function to approach the singularity. Finally, it is interesting that turbulence can be controlled by modulating the distribution of the energy gradient function.