J4 ›› 2012, Vol. 9 ›› Issue (4): 457-464.doi: 10.1016/S1672-6529(11)60140-6

• 论文 • 上一篇    下一篇

Bionic Research on Fish Scales for Drag Reduction

Zhaoliang Dou, Jiadao Wang, Darong Chen   

  1. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P. R. China
  • 出版日期:2012-12-30
  • 通讯作者: Zhaoliang Dou E-mail:douzl05@mails.tsinghua.edu.cn

Bionic Research on Fish Scales for Drag Reduction

Zhaoliang Dou, Jiadao Wang, Darong Chen   

  1. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P. R. China
  • Online:2012-12-30
  • Contact: Zhaoliang Dou E-mail:douzl05@mails.tsinghua.edu.cn

摘要:

To reduce friction drag with bionic method in a more feasible way, the surface microstructure of fish scales was analyzed attempting to reveal the biologic features responding to skin friction drag reduction. Then comparable bionic surface mimicking fish scales was fabricated through coating technology for drag reduction. The paint mixture was coated on a substrate through a self-developed spray-painting apparatus. The bionic surface with micron-scale caves formed spontaneously due to the interfacial convection and deformation driven by interfacial tension gradient in the presence of solvent evaporation. Comparative experiments between bionic surface and smooth surface were performed in a water tunnel to evaluate the effect of bionic surface on drag reduction, and visible drag reduction efficiency was obtained. Numerical simulation results show that gas phase develops in solid-liquid interface of bionic surface with the effect of surface topography and partially replaces the solid-liquid shear force with gas-liquid shear force, hence reducing the skin friction drag effectively. Therefore, with remarkable drag reduction performance and simple fabrication technology, the proposed drag reduction technique shows the promise for practical applications.

关键词: drag reduction, micro-structured bionic surface, fish scales, polymer coating, interfacial convection and deformation

Abstract:

To reduce friction drag with bionic method in a more feasible way, the surface microstructure of fish scales was analyzed attempting to reveal the biologic features responding to skin friction drag reduction. Then comparable bionic surface mimicking fish scales was fabricated through coating technology for drag reduction. The paint mixture was coated on a substrate through a self-developed spray-painting apparatus. The bionic surface with micron-scale caves formed spontaneously due to the interfacial convection and deformation driven by interfacial tension gradient in the presence of solvent evaporation. Comparative experiments between bionic surface and smooth surface were performed in a water tunnel to evaluate the effect of bionic surface on drag reduction, and visible drag reduction efficiency was obtained. Numerical simulation results show that gas phase develops in solid-liquid interface of bionic surface with the effect of surface topography and partially replaces the solid-liquid shear force with gas-liquid shear force, hence reducing the skin friction drag effectively. Therefore, with remarkable drag reduction performance and simple fabrication technology, the proposed drag reduction technique shows the promise for practical applications.

Key words: drag reduction, micro-structured bionic surface, fish scales, polymer coating, interfacial convection and deformation