Analysis of conditional statistics obtained near the turbulent/non-turbulent interface of turbulent boundary layers

Takashi Ishihara, Hiroki Ogasawara, Julian C.R. Hunt

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Direct numerical simulations of turbulent boundary layers (TBL) along a flat plate are used to study the properties of turbulent/non-turbulent (T/NT) interface of the TBL. The values of the momentum-thickness-based Reynolds numbers, Reθ, used for this study, are 500-2200. Analysis of the conditional statistics near the interface of the TBL shows that there are a small peak in the spanwise vorticity, and an associated small jump in streamwise velocity. It is shown that the interfacial layer has an inertia-viscous double structure which consists of a turbulent sublayer with a thickness of the order of the Taylor micro-scale and its outer boundary with a thickness of the order of the Kolmogorov length scale. The velocity jump near the T/NT interface of the TBL is of the order of the rms value of velocity fluctuations near the interface. Conditional cross correlations of the streamwise or the wall-normal velocity fluctuations change sharply across the interface, which are consistent with the blocking mechanism of the interface.

Original languageEnglish
Pages (from-to)50-57
Number of pages8
JournalJournal of Fluids and Structures
Volume53
DOIs
Publication statusPublished - Feb 1 2015
Externally publishedYes

Keywords

  • Blocking mechanism
  • Conditional statistics
  • Turbulent boundary layer
  • Turbulent/non-turbulent interface

ASJC Scopus subject areas

  • Mechanical Engineering

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