Turbulent characteristics of a flowfield over a heated riblet surface

Kazumi Tsunoda, Mitsuhiro Kurihara

Research output: Contribution to journalArticlepeer-review

Abstract

Experimental studies of a turbulent flowfield developing over the heated riblet surface were carried out in a low-speed wind tunnel. The instantaneous velocity fields were measured by using a particle image velocimetry (PIV) in a plane that was parallel to the riblet surface, and compared with those over a heated smooth surface. The reduction ratio of the skin friction coefficient over the heated riblet surface reached up to 8% for the riblet spacing of about 13 viscous wall units. This is almost the same spacing as that obtained for the non-heated condition. The streamwise and wall-normal turbulent intensities against the local time-mean velocity were decreased in their peak values for the heated riblet. The instantaneous fluctuating velocity fields obtained by subtracting the ensemble-averaged velocity from instantaneous velocity vectors revealed that the appearance of a low-speed streaky structure became more intermittent over the riblet surface. This fact suggested a reduction in turbulence production in the near-wall region. Furthermore, it was also found that a perturbation of the spanwise velocity fluctuation was restricted near the riblet surface.

Original languageEnglish
Pages (from-to)818-825
Number of pages8
JournalNihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
Volume74
Issue number4
DOIs
Publication statusPublished - 2008 Apr

Keywords

  • Particle image velocimetry
  • Riblet
  • Skin friction coefficient
  • Streaky structure
  • Turbulence
  • Turbulent flow

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering

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