This paper presents an experimental study of horizontal channel flow with air-filled superhydrophobic grooves. Air–water interfaces in the grooves are visualized in a range of the channel Reynolds number, Re, (2000 ≤ Re ≤ 5000) while flow characteristics are evaluated using particle tracking velocimetry measurements at Re = 3000 and 4000. Near the air–water interface in the superhydrophobic groove, turbulent eddies and hence the Reynolds shear stress appreciably attenuate owing to a lack of energy supply through the interface, and it takes a notable distance for the Reynolds shear stress to recover downstream of the groove. Additionally, a secondary cross-flow from the solid surface region between two grooves towards the air–water interface appears and sweeps eddies between the grooves towards the interface. The decay of turbulent eddies and the sweeping of eddies from the solid surface to the air–water interface reduce friction drag both in and immediately downstream of the grooved region.

中文翻译：

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由于充满空气的超疏水凹槽，瞬态速度分布和减阻

本文介绍了具有充气超疏水凹槽的水平通道流动的实验研究。凹槽中的空气-水界面在通道雷诺数 Re (2000 ≤ Re ≤ 5000) 的范围内可视化，同时使用 Re = 3000 和 4000 处的粒子跟踪测速测量评估流动特性。 靠近空气-水界面在超疏水凹槽中，由于缺乏通过界面的能量供应，湍流涡流和雷诺剪应力明显减弱，并且雷诺剪应力在凹槽下游恢复需要很长的距离。此外，从两个凹槽之间的固体表面区域向空气-水界面出现二次交叉流，并将凹槽之间的涡流扫向界面。