论文标题
穿孔板上的渗透性和湍流
Permeability and turbulence over perforated plates
论文作者
论文摘要
我们直接对摩擦雷诺数的湍流进行直接数值模拟，$re_τ\re_τ\约500-2000 $放牧对带有中等粘性的孔口直径$ d^+d^+\ yout 40 $ - $ 160 $的穿孔板，并分析了渗透率和备用性之间的关系。与以前对渗透性表面上的湍流的研究不同，我们发现孔口内部的流量主要由惯性效应支配，并且相关的渗透性是forchheimer而不是达西的渗透性。我们找到了一个完全粗糙的状态的证据，其中相关的长度尺度是Forchheimer系数的倒数，这可以视为壁正常流量所经历的电阻。此外，我们表明，对于低孔隙率，可以使用简单的分析关系以良好的精度估算Forchheimer系数。
We perform direct numerical simulations of turbulent flow at friction Reynolds number $Re_τ\approx 500-2000$ grazing over perforates plates with moderate viscous-scaled orifice diameter $d^+\approx40$--$160$ and analyse the relation between permeability and added drag. Unlike previous studies of turbulent flows over permeable surfaces, we find that flow inside the orifices is dominated by inertial effects, and that the relevant permeability is the Forchheimer and not the Darcy one. We find evidence of a fully rough regime where the relevant length scale is the inverse of the Forchheimer coefficient, which can be regarded as the resistance experienced by the wall-normal flow. Moreover, we show that, for low porosities, the Forchheimer coefficient can be estimated with good accuracy using a simple analytical relation.
