Air-assisted drag reduction promoted by hydrophobic attraction

Abstract

Hydrophobic property is of vital significance to entrap air between the solid surface and liquid. In this paper, we observed the formation of air pockets anchored on the wetting solid surface during the lubrication process. It reveals that the fabrication surfaces with various microstructures may achieve different drag reduction effect by using air pockets. The simulation method was presented to visualize the air-solid interface, and obtain the insights of the relationship between the hydrophobic and air-assisted drag reduction. The high hydrophobicity results high drag reduction. And in the paper, it was found that the pit-type micro-texture with the best hydrophobic effect has a significant positive effect on drag reduction, because 90.56% of the solid-liquid interface is replaced by the air-liquid interface.

Graphical Abstract

Keywords:

• Pit-type micro-texture
• air lubrication
• friction coefficient

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (Grant Nos. 51875417 and 51975425) and the National Key R&D Program of China 2021YFB2011200. The authors gratefully acknowledge this support.