Friction drag reduction achievable by near-wall turbulence manipulation at high Reynolds numbers
Friction drag reduction achievable by near-wall turbulence manipulation at high Reynolds numbers
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DOI：
10.1063/1.1827276
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发表时间：
2005
影响因子：
4.6
通讯作者：
K. Iwamoto;K. Fukagata;N. Kasagi;Yuji Suzuki
中科院分区：
文献类型：
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作者：
K. Iwamoto;K. Fukagata;N. Kasagi;Yuji Suzuki
阐明了通过将近壁湍流速度脉动减小到零来实现减阻的雷诺数依赖关系。这种简化可以通过虚拟的主动反馈控制系统来实现。推导出的公式表明，如果壁面附近的湍流脉动被完全抑制，即使在高雷诺数的情况下，也可以获得较大的减阻效果。例如，如果湍流只在y+=10以下消失，则在Reτ=105时可以获得35%的减阻率。因此，主要研究低雷诺数的主动反馈控制策略，即使在实际应用中的高雷诺数流动中也是很有前途的。文中还给出了雷诺数Reτ=642时槽道湍流的直接数值模拟结果，以阐明控制流动中的现象。
The Reynolds-number dependence of the drag reduction achievable by diminishing to zero the near-wall turbulent velocity fluctuations is clarified. This reduction could be obtained by a virtual active feedback control system. The formula derived suggests that large drag reduction can be attained even at high Reynolds numbers if turbulence fluctuations adjacent to the wall are completely damped. For example, 35% drag reduction rate can be obtained at Reτ=105 if the turbulence only below y+=10 vanishes. Thus, the active feedback control strategy, which has been studied mostly at low Reynolds numbers, would be much promising even in high Reynolds number flows of real applications. Results from the direct numerical simulation of turbulent channel flow at a Reynolds number of Reτ=642 are also presented to clarify the phenomena in the controlled flow.