Tribology and Lubricants

Korean Tribology Society (한국트라이볼로지학회)
권호 표지
DOI QR코드

DOI QR Code

Simulation for Contact Angle of Droplet on Riblet Surface

  • Kim, Tae Wan (Dept. of Mechanical Engineering, Pukyong National University)
  • Received : 2017.08.27
  • Accepted : 2017.09.21
  • Published : 2017.10.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the hydrophobicity properties for riblet surfaces that replicate shark skin are simulated. Riblet surfaces with surface roughness on riblets are generated numerically based on the measured data of real shark skin. We assumed that a rib on a scale is hemi-elliptical surface. The surface used in the simulation for the calculation of contact angle is composed of 9 scales like checkerboard type with a roughness. The contact angle of a water droplet can be calculated using the Wenzel equation and Cassie-Baxter equation for the generated riblet surfaces. The variation of contact angles with a fractional depth of penetration for the generated shark skin surfaces without and with coatings is demonstrated in the condition of solid-air-water. The results show that the contact angle for the surface without coating decreases with an increase of the fractional depth of penetration more drastically than that for the surface with coating. We compared the experimental and simulated results. It is shown that the measured contact angles of the shark skin template and the shark skin replica are within the simulated results. Therefore the contact angle of water droplet for rough surfaces can be estimated by the developed numerical method in this study.

Keywords

References

  1. C. Büttner, U. Schulz, "Shark skin inspired riblet coatings for aerodynamically optimized high temperature applications in aeroengines", Adv. Eng. Mater., Vol. 13, pp. 288-295, 2011. https://doi.org/10.1002/adem.201000265
  2. W. Sagong, C. Kim, S. Choi, W. -P. Jeon, H. Choi, "Does the sailfish reduce the skin friction like the the shark skin?", Phys. Fluids, Vol. 20, pp. 101510, 2008. https://doi.org/10.1063/1.3005861
  3. Y. C. Jung, B. Bhushan, "Biomimetic structures for fluid drag reduction in laminar and turbulent flows", J. Phys. Condens. Matter., Vol. 22, pp. 035104, 2010. https://doi.org/10.1088/0953-8984/22/3/035104
  4. J. F. Schumacher, M. L. Carman, T. G. Estes, A. W. Feinberg, L. H. Wilson, M. E. Callow, J. A. Callow, J. A. Finlay, A. B. Brennan, "Engineered antifouling microtopographies - effect of feature size, geometry, and roughness on settlement of zoospores of the green alga Ulva," Biofouling, Vol. 23, pp. 55-62, 2007. https://doi.org/10.1080/08927010601136957
  5. S. J. Lee, Y. G. Jang, "Control offlow around a NACA 0012 airfoil with a micro-riblet film", J. Fluids, Vol. 20, pp. 659-672, 2005.
  6. D. Y. Zhang, Y. Y. Li, X. Han, X. Li, H. W. Chen, "High-precision bio-replication of synthetic drag reduction shark skin", Chinese Sci. Bull., Vol. 56, pp. 938-944, 2011. https://doi.org/10.1007/s11434-010-4163-7
  7. Y. Liu, G. Li, "A new method for producing "Lotus Effect" on a biomimetic shark skin", J Colloid Interface Sci., Vol. 388, pp. 235-242, 2012. https://doi.org/10.1016/j.jcis.2012.08.033
  8. T. W. Kim, "Asseessment of Hydro/Oleophobicity for shark skin replica with riblets", J Nanosci Nanotechnol. Vol. 14. pp.7562-7568, 2014. https://doi.org/10.1166/jnn.2014.9570
  9. Y. S. Kong, T. W. Kim, "Wettability of biomimetic riblet surface like sharkskin", J. Korean Soc. Tribol. Lubr. Eng., Vol. 29, No. 10, pp. 304-309, 2013.

Cited by

  1. 리블렛 표면에서 유적의 젖음성에 대한 수치 해석 vol.35, pp.2, 2017, https://doi.org/10.9725/kts.2019.35.2.94