Modulation of near-wall turbulence in the transitionally rough regime
Modulation of near-wall turbulence in the transitionally rough regime
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过渡粗糙状态下近壁湍流的调制
DOI：
10.1017/jfm.2019.41
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发表时间：
2019
影响因子：
3.7
通讯作者：
Abderrahaman-Elena N
中科院分区：
文献类型：
--
作者：
Abderrahaman-Elena N
在过渡粗糙区对粗糙壁湍流通道进行了直接数值模拟。粗糙度上覆湍流产生的效果进行了研究，使用修改后的三重分解的流量。这种分解将粗糙度引起的贡献与背景湍流分离，后者基本上没有任何纹理足迹。对于小的粗糙度，背景湍流没有显著改变，而只是位移更接近粗糙度峰，阻力的变化与此位移成正比。随着粗糙度尺寸的增加，背景湍流开始被修改，特别是通过增加短，宽波长的能量，这是一致的外观的剪切流不稳定的平均流。提出了一个层流模型来估计粗糙相干的贡献，以及在粗糙峰的位移高度和速度。基于在背景湍流中观察到的影响，粗糙度函数被分解成不同的项，以分析对阻力变化的不同贡献，为预测模型奠定基础。
Direct numerical simulations of turbulent channels with rough walls are conducted in the transitionally rough regime. The effect that roughness produces on the overlying turbulence is studied using a modified triple decomposition of the flow. This decomposition separates the roughness-induced contribution from the background turbulence, with the latter essentially free of any texture footprint. For small roughness, the background turbulence is not significantly altered, but merely displaced closer to the roughness crests, with the change in drag being proportional to this displacement. As the roughness size increases, the background turbulence begins to be modified, notably by the increase of energy for short, wide wavelengths, which is consistent with the appearance of a shear-flow instability of the mean flow. A laminar model is presented to estimate the roughness-coherent contribution, as well as the displacement height and the velocity at the roughness crests. Based on the effects observed in the background turbulence, the roughness function is decomposed into different terms to analyse different contributions to the change in drag, laying the foundations for a predictive model.
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关于“临界粗糙度高度”和“过渡粗糙度”的注释
影响因子：
4.6
作者：
P. Bradshaw
通讯作者：
P. Bradshaw
影响因子：
3.7
作者：
M. Thakkar;Angela Busse;N. Sandham
通讯作者：
M. Thakkar;Angela Busse;N. Sandham
影响因子：
4.6
作者：
K. Flack;M. Schultz;Jonathan S. Connelly
通讯作者：
K. Flack;M. Schultz;Jonathan S. Connelly
影响因子：
1.9
作者：
P. Orlandi;S. Leonardi
通讯作者：
P. Orlandi;S. Leonardi
DOI：
--
发表时间：
2017
期刊：
Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena
影响因子：
--
作者：
Akshath Sharma;G. Gómez;R. García
通讯作者：
R. García