Structural organization of large and very large scales in turbulent pipe flow simulation

J. R. Baltzer, Ronald Adrian, Xiaohua Wu

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

The physical structures of velocity are examined from a recent direct numerical simulation of fully developed incompressible turbulent pipe flow (Wu, Baltzer & Adrian, J. Fluid Mech., vol. 698, 2012, pp. 235-281) at a Reynolds number of ReD = 240580 (based on bulk velocity) and a Kármán number of R+ = 685. In that work, the periodic domain length of 30 pipe radii R was found to be sufficient to examine long motions of negative streamwise velocity fluctuation that are commonly observed in wall-bounded turbulent flows and correspond to the large fractions of energy present at very long streamwise wavelengths (≥3R). In this paper we study how long motions are composed of smaller motions. We characterize the spatial arrangements of very large-scale motions (VLSMs) extending through the logarithmic layer and above, and we find that they possess dominant helix angles (azimuthal inclinations relative to streamwise) that are revealed by two-and three-dimensional two-point spatial correlations of velocity. The correlations also reveal that the shorter, large-scale motions (LSMs) that concatenate to comprise the VLSMs are themselves more streamwise aligned. We show that the largest VLSMs possess a form similar to roll cells centred above the logarithmic layer and that they appear to play an important role in organizing the flow, while themselves contributing only a minor fraction of the flow turbulent kinetic energy. The roll cell motions play an important role with the smaller scales of motion that are necessary to create the strong streamwise streaks of low-velocity fluctuation that characterize the flow.

Original languageEnglish (US)
Pages (from-to)236-279
Number of pages44
JournalJournal of Fluid Mechanics
Volume720
DOIs
StatePublished - Apr 2013

Fingerprint

pipe flow
Flow simulation
Pipe flow
simulation
Turbulent flow
Direct numerical simulation
turbulent flow
Kinetic energy
Reynolds number
Pipe
Wavelength
organizing
Fluids
cells
direct numerical simulation
helices
low speed
inclination
kinetic energy
radii

Keywords

  • turbulent boundary layers
  • turbulent flows

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Condensed Matter Physics

Cite this

Structural organization of large and very large scales in turbulent pipe flow simulation. / Baltzer, J. R.; Adrian, Ronald; Wu, Xiaohua.

In: Journal of Fluid Mechanics, Vol. 720, 04.2013, p. 236-279.

Research output: Contribution to journalArticle

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