A deterministic model for the sublayer streaks in turbulent boundary layers for application to flow control
A deterministic model for the sublayer streaks in turbulent boundary layers for application to flow control
复制标题
用于流动控制的湍流边界层子层条纹的确定性模型
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Christopher Davies
中科院分区：
文献类型：
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作者：
P. Carpenter;K. Kudar;Reza Ali;P. K. Sen;Christopher Davies
我们提出了一个相对简单的，确定性的，在湍流边界层的基础上与Klebanoff模式类比的子层条纹的理论模型。我们的方法是通过虚拟体积力形式的涡源产生缓冲层中的流向涡。据发现，最强的条纹对应于展向波长的统计平均条纹间距的实验观察值的范围内。我们还提出的结果显示，流向压力梯度的影响，雷诺数和壁面顺应性上的子层条纹。壁面顺应性对条纹特性影响的理论预测与实验数据吻合得很好。我们提出的准周期爆发周期的理论模型也进行了描述，其中的条纹建模的背景下。所提出的破裂过程如下：（i）流向涡产生亚层条纹，其他涡元产生传播的平面波，（ii）当条纹达到足够的振幅时，它们与平面波非线性地相互作用，产生表现出瞬态增长的斜波，（iii）斜波与平面波非线性地相互作用，产生流向涡;这些又产生子层条纹，因此循环被更新。
We present a relatively simple, deterministic, theoretical model for the sublayer streaks in a turbulent boundary layer based on an analogy with Klebanoff modes. Our approach is to generate the streamwise vortices found in the buffer layer by means of a vorticity source in the form of a fictitious body force. It is found that the strongest streaks correspond to a spanwise wavelength that lies within the range of the experimentally observed values for the statistical mean streak spacing. We also present results showing the effect of streamwise pressure gradient, Reynolds number and wall compliance on the sublayer streaks. The theoretical predictions for the effects of wall compliance on the streak characteristics agree well with experimental data. Our proposed theoretical model for the quasi-periodic bursting cycle is also described, which places the streak modelling in context. The proposed bursting process is as follows: (i) streamwise vortices generate sublayer streaks and other vortical elements generate propagating plane waves, (ii) when the streaks reach a sufficient amplitude, they interact nonlinearly with the plane waves to produce oblique waves that exhibit transient growth, and (iii) the oblique waves interact nonlinearly with the plane wave to generate streamwise vortices; these in turn generate the sublayer streaks and so the cycle is renewed.