Drag-reducing performance of obliquely aligned superhydrophobic surface in turbulent channel flow

Sho Watanabe, Hiroya Mamori, Koji Fukagata

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Friction drag reduction effect by superhydrophobic surfaces in a turbulent channel flow is investigated by means of direct numerical simulation. The simulations are performed under a constant pressure gradient at the friction Reynolds number of 180. A special focus is laid upon the influence of the angle of microridge structure to flow direction, while the gas area fraction on the surface is kept at 50% and the groove width is kept constant at 33.75 wall units. Larger drag reduction effect is observed for a smaller angle: the bulk-mean velocity is increased about 15% when the microridge is parallel to the flow. The drag reduction effect is found to deteriorate rapidly with the microridge angle due to a decrease in the slip velocity. The Reynolds stress budgets show that the modification in each physical effect is qualitatively similar but more pronounced when the microridge is aligned with the stream.

Original languageEnglish
Article number025501
JournalFluid Dynamics Research
Volume49
Issue number2
DOIs
Publication statusPublished - 2017 Jan 17

Keywords

  • direct numerical simulation
  • drag reduction
  • superhydrophobic surface
  • turbulence

ASJC Scopus subject areas

  • Mechanical Engineering
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes

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