Analysis of anisotropically permeable surfaces for turbulent drag reduction
Analysis of anisotropically permeable surfaces for turbulent drag reduction
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DOI：
10.1103/physrevfluids.2.114609
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发表时间：
2017-11-30
影响因子：
2.7
通讯作者：
Garcia-Mayoral, Ricardo
中科院分区：
文献类型：
--
作者：
Abderrahaman-Elena, Nabil;Garcia-Mayoral, Ricardo
本工作提出了使用各向异性渗透基板作为一种手段，以减少湍流表面摩擦。我们进行了先验分析，以评估这些表面的潜力，基于小规模的表面操作对近壁湍流的影响。该分析，有效的小渗透率，预测的单调减少摩擦的流向渗透率增加。经验结果表明，然而，阻力减少机制是注定要失败超过一定的渗透率。我们调查的发展开尔文-亥姆霍兹像辊的表面作为一个潜在的机制，这种故障。这些辊是可渗透壁上方湍流的典型特征，已知其增加阻力，并且已知其外观限制了减阻效果。我们提出了一个模型，线性稳定性分析的基础上，预测这些辊足够大的渗透率的发病，并允许我们约束这些表面可以实现的最大减阻。
The present work proposes the use of anisotropically permeable substrates as a means to reduce turbulent skin friction. We conduct an a priori analysis to assess the potential of these surfaces, based on the effect of small-scale surface manipulations on near-wall turbulence. The analysis, valid for small permeability, predicts a monotonic decrease in friction as the streamwise permeability increases. Empirical results suggest that the drag-reducing mechanism is however bound to fail beyond a certain permeability. We investigate the development of Kelvin-Helmholtz-like rollers at the surface as a potential mechanism for this failure. These rollers, which are a typical feature of turbulent flows over permeable walls, are known to increase drag and their appearance is known to limit the drag-reducing effect. We propose a model, based on linear stability analysis, that predicts the onset of these rollers for sufficiently large permeability and allows us to bound the maximum drag reduction that these surfaces can achieve.