Drag reduction and hairpin packets of the turbulent boundary layer over the superhydrophobic-riblets surface
Drag reduction and hairpin packets of the turbulent boundary layer over the superhydrophobic-riblets surface
复制标题
超疏水肋表面上湍流边界层的减阻和发夹包
DOI：
10.1007/s42241-021-0057-1
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发表时间：
2021-06
影响因子：
2.5
通讯作者：
Nan Jiang
中科院分区：
文献类型：
--
作者：
Xin-wei Wang;Zi-ye Fan;Zhan-qi Tang;Nan Jiang
利用时间分辨粒子图像速度场仪（TR-PIV）对开式循环水槽中光滑表面、超疏水表面和超疏水沟槽表面的湍流边界层进行了实验测量。基于壁面摩擦速度和TBL在光滑表面上的厚度的雷诺数为702。利用激光毛化技术分别在光滑表面和沟槽表面上加工出SH表面和SR表面。采用（改进的）Clauser方法，SR表面的减阻率约为22.1%，而SH表面的减阻率约为18.7%，具有上级减阻效果。与SH表面相比，SR表面在近壁区的二阶统计量下降也表明SR表面的阻力显著降低。通过正交分解提取的大尺度结构分量在+> 40区域产生了大部分的雷诺剪应力。在不同的壁法线位置的粗糙表面（SH和SR表面）的大规模功能的强度可视化的象限分裂方法和条件平均。大尺度结构的出现，如发夹包特征的两点相关显示出良好的一致性与统计轮廓。SH表面上的发夹包似乎总是比光滑表面上的发夹包更小和更弱。在SR表面上，0.1 ≤yδ < 0.3区域的发夹包最小，强度最弱，而在0.3 <yδ < 0.6区域，发夹包的规模和强度超过光滑表面.
This paper presents experimental measurements by the time-resolved particle image velocimetry (TR-PIV) for the turbulent boundary layer (TBL) over the smooth surface, the superhydrophobic (SH) surface, and the superhydrophobic-riblets (SR) surface in an open-surface recirculating water channel. The Reynolds number based on the wall friction velocity and the thickness of the TBL over the smooth surface is 702. The SH surface and the SR surface are manufactured by the laser texturing method on the smooth surface and the riblets surface, respectively. By employing the (modified) Clauser method, a superior efficacy of the drag reduction of about 22.1% is obtained on the SR surface, while the drag reduction rate for the SH surface is about 18.7%. Comparing with the SH surface, the declining 2-order statistics in the near-wall region also indicates a significant drag reduction over the SR surface. The large-scale structure components extracted by the proper orthogonal decomposition are found to generate a majority of the Reynolds shear stress in the regiony+> 40. The strength of the large-scale features over the rough surfaces (SH and SR surfaces) at disparate wall-normal positions is visualized by the Quadrant splitting method and the conditional averaging. The appearance of the large-scale structures such as the hairpin packets characterized by the two-point correlation shows an excellent consistency with the statistics profile. The hairpin packets over the SH surface seem always smaller and weaker than those over the smooth surface. Over the SR surface, the hairpin packets in the region 0.1 ≤yδ < 0.3 are the smallest and weakest among those over the three surfaces, while the scale and the strength of the hairpin packets exceed those over the smooth surface in the region 0.3 <yδ < 0.6.
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影响因子：
3.7
作者：
Chengyue Wang;Q. Gao;Jinjun Wang;Biao Wang;C. Pan
通讯作者：
Chengyue Wang;Q. Gao;Jinjun Wang;Biao Wang;C. Pan
DOI：
10.1016/j.expthermflusci.2018.02.001
发表时间：
2018-06-01
影响因子：
3.2
作者：
Abu Rowin, Wagih;Hou, Jianfeng;Ghaemi, Sina
通讯作者：
Ghaemi, Sina
影响因子：
2.5
作者：
Hao Lu
通讯作者：
Hao Lu
影响因子：
3.7
作者：
A. Perry;J. D. Li
通讯作者：
A. Perry;J. D. Li
影响因子：
3.7
作者：
K. Kevin;J. Monty;H. Bai;G. Pathikonda;B. Nugroho;J. Barros;K. Christensen;N. Hutchins
通讯作者：
K. Kevin;J. Monty;H. Bai;G. Pathikonda;B. Nugroho;J. Barros;K. Christensen;N. Hutchins