RT Journal Article
SR Electronic
T1 Significant and stable drag reduction with air rings confined by alternated superhydrophobic and hydrophilic strips
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP e1603288
DO 10.1126/sciadv.1603288
VO 3
IS 9
A1 Hu, Haibao
A1 Wen, Jun
A1 Bao, Luyao
A1 Jia, Laibing
A1 Song, Dong
A1 Song, Baowei
A1 Pan, Guang
A1 Scaraggi, Michele
A1 Dini, Daniele
A1 Xue, Qunji
A1 Zhou, Feng
YR 2017
UL http://advances.sciencemag.org/content/3/9/e1603288.abstract
AB Superhydrophobic surfaces have the potential to reduce the viscous drag of liquids by significantly decreasing friction at a solid-liquid interface due to the formation of air layers between solid walls and interacting liquids. However, the trapped air usually becomes unstable due to the finite nature of the domain over which it forms. We demonstrate for the first time that a large surface energy barrier can be formed to strongly pin the three-phase contact line of air/water/solid by covering the inner rotor of a Taylor-Couette flow apparatus with alternating superhydrophobic and hydrophilic circumferential strips. This prevents the disruption of the air layer, which forms stable and continuous air rings. The drag reduction measured at the inner rotor could be as much as 77.2%. Moreover, the air layers not only significantly reduce the strength of Taylor vortexes but also influence the number and position of the Taylor vortex pairs. This has strong implications in terms of energy efficiency maximization for marine applications and reduction of drag losses in, for example, fluid transport in pipelines and carriers.