Turbulence structure of multiscale generated turbulence by fractal grids and scalar transfer mechanism (2nd report, DNS on the influence of grid parameters on homogeneity, isotropy and intermittency)

Hiroki Suzuki, Kouji Nagata, Yasuhiko Sakai, Toshiyuki Hayase

Research output: Contribution to journalArticlepeer-review

Abstract

Turbulence characteristics in the spatially developing fractal-generated turbulence are investigated by means of the direct numerical simulation (DNS). The square type fractal grids are numerically constructed using the immersed boundary method. The effects of solidity σ and thickness ratio t r, which are ones of the most important grid parameters for fractal grids, are investigated in detail. The results show that the increase of a leads to the improvement of the uniformity and isotropy of flow fields. The integral length scale in the decaying region of the fractal-generated turbulence remains monotone increase at high σ and tr, whereas it is approximately constant at low σ and tr. The derivative skewness and flatness in the streamwise direction are different from those in the transverse direction for all σ and tr investigated. These results will be useful for designing fractal grids for practical applications.

Original languageEnglish
Pages (from-to)2024-2031
Number of pages8
JournalNihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
Volume76
Issue number772
DOIs
Publication statusPublished - 2010 Dec

Keywords

  • Computational fluid dynamics
  • Direct numerical simulation
  • Finite difference method
  • Fractal
  • Grid-Generated turbulence
  • Turbulence

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering

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