TY - JOUR
T1 - Bioinspired universal approaches for cavity regulation during cylinder impact processes for drag reduction in aqueous media
T2 - macrogeometry vanquishing wettability
AU - Yao, Changzhuang
AU - Zhou, Yanjiao
AU - Wang, Jingming
AU - Jiang, Lei
N1 - Funding Information:
This work was financially supported by the National Natural Science Foundation of China (21975008), the Key Research Program of the Chinese Academy of Sciences (KJZD-EW-M01), the 111 Project (B14009), the Beijing Higher Education Young Elite Teacher Project, and the Fundamental Research Funds for the Central Universities.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/8/18
Y1 - 2021/8/18
N2 - Stabilizing lubricating gas films at the solid-liquid interface is a promising strategy for underwater drag reduction. It has been restricted by the enormous extra energy input and the poor stability of superhydrophobic coatings. Cavity encapsulation is a valid method to improve and maintain the formation of the air layer on the solid surface, which is created by the rapidly impacting process on a water surface. The wettability of solid objects (the combination of the surface roughness and chemical component) and liquid properties played a key factor in determining the water impact process for cavity entrainment. However, inspired by the striking behavior of basilisk lizards and their toe's shape, we found that the geometric shape of solid objects plays an equally important role in cavity entrainment and stabilization, which is often ignored. Herein, we present a universal strategy to retain the air cavity on the cylinder surfaces. The cavity can be retained not only on the surface of superhydrophobic cylinders but also on the surface of hydrophobic, hydrophilic, and even superhydrophilic cylinders, without bursting at a depth of 70.0-90.0 cm underwater. The retaining cavity enfolds the profile and upper sides of the cylinder and changes its shape to a streamlined body to achieve underwater drag reduction. In addition, optimizing the cylinders' shapes by increasing the fillet radii significantly improved the drag reduction efficiency from 64.2 to 70.5%.
AB - Stabilizing lubricating gas films at the solid-liquid interface is a promising strategy for underwater drag reduction. It has been restricted by the enormous extra energy input and the poor stability of superhydrophobic coatings. Cavity encapsulation is a valid method to improve and maintain the formation of the air layer on the solid surface, which is created by the rapidly impacting process on a water surface. The wettability of solid objects (the combination of the surface roughness and chemical component) and liquid properties played a key factor in determining the water impact process for cavity entrainment. However, inspired by the striking behavior of basilisk lizards and their toe's shape, we found that the geometric shape of solid objects plays an equally important role in cavity entrainment and stabilization, which is often ignored. Herein, we present a universal strategy to retain the air cavity on the cylinder surfaces. The cavity can be retained not only on the surface of superhydrophobic cylinders but also on the surface of hydrophobic, hydrophilic, and even superhydrophilic cylinders, without bursting at a depth of 70.0-90.0 cm underwater. The retaining cavity enfolds the profile and upper sides of the cylinder and changes its shape to a streamlined body to achieve underwater drag reduction. In addition, optimizing the cylinders' shapes by increasing the fillet radii significantly improved the drag reduction efficiency from 64.2 to 70.5%.
KW - air-entrained cavity
KW - bioinspired
KW - cylinder
KW - drag reduction
KW - fillet radii
KW - geometric shape
UR - http://www.scopus.com/inward/record.url?scp=85113300399&partnerID=8YFLogxK
U2 - 10.1021/acsami.1c06846
DO - 10.1021/acsami.1c06846
M3 - Article
C2 - 34347428
AN - SCOPUS:85113300399
SN - 1944-8244
VL - 13
SP - 38808
EP - 38815
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 32
ER -