Zhang Liangpei, Wan Xia, Zhou Xu, Cao Yanlin, Duan Huiling, Yan Jiale, Li Hongyuan, Lv Pengyu
State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, P. R. China.
Laoshan Laboratory, Qingdao 266237, P. R. China.
ACS Appl Mater Interfaces. 2024 Aug 21;16(33):44319-44327. doi: 10.1021/acsami.4c09631. Epub 2024 Aug 7.
Superhydrophobic surfaces hold immense potential in underwater drag reduction. However, as the Reynolds number increases, the drag reduction rate decreases, and it may even lead to a drag increase. The reason lies in the collapse of the air mattress. To address this issue, this paper develops a pyramid-shaped robust superhydrophobic surface with wedged microgrooves, which exhibits a high gas fraction when immersed underwater and good ability to achieve complete spreading and recovery of the air mattress through air replenishment in the case of collapse of the air mattress. Pressure drop tests in a water tunnel confirm that with continuous air injection, the drag reduction reaches 64.8% in laminar flow conditions, substantially greater than 38.4% in the case without air injection, and can achieve 50.8% drag reduction in turbulent flow. This result highlights the potential applications of superhydrophobic surfaces with air mattress recovery for drag reduction.
超疏水表面在水下减阻方面具有巨大潜力。然而，随着雷诺数的增加，减阻率会降低，甚至可能导致阻力增加。原因在于气垫的坍塌。为了解决这个问题，本文开发了一种带有楔形微槽的金字塔形坚固超疏水表面，该表面在水下浸没时具有高气体分数，并且在气垫坍塌的情况下能够通过空气补充实现气垫的完全铺展和恢复。在水洞中进行的压降测试证实，通过持续注入空气，在层流条件下减阻率达到64.8%，大大高于不注入空气时的38.4%，在湍流中也能实现50.8%的减阻。这一结果突出了具有气垫恢复功能的超疏水表面在减阻方面的潜在应用。
