Large- and very-large-scale motions in channel and boundary-layer flows

B. J. Balakumar, Ronald Adrian

Research output: Contribution to journalArticlepeer-review

308 Scopus citations

Abstract

Large-scale motions (LSMs; having wavelengths up to 2-3 pipe radii) and very-LSMs (having wavelengths more than 3 pipe radii) have been shown to carry more than half of the kinetic energy and Reynolds shear stress in a fully developed pipe flow. Studies using essentially the same methods of measurement and analysis have been extended to channel and zero-pressure-gradient boundary-layer flows to determine whether large structures appear in these canonical wall flows and how their properties compare with that of the pipe flow. The very large scales, especially those of the boundary layer, are shorter than the corresponding scales in the pipe flow, but otherwise share a common behaviour, suggesting that they arise from similar mechanism(s) aside from the modifying influences of the outer geometries. Spectra of the net force due to the Reynolds shear stress in the channel and boundary layer flows are similar to those in the pipe flow. They show that the very-largescale and main turbulent motions act to decelerate the flow in the region above the maximum of the Reynolds shear stress.

Original languageEnglish (US)
Pages (from-to)665-681
Number of pages17
JournalPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume365
Issue number1852
DOIs
StatePublished - Mar 15 2007

Keywords

  • Channel flow
  • Hairpin-vortex packets
  • Large-scale motions
  • Long-wavelength motions
  • Travelling wave solutions
  • Very-large-scale motions

ASJC Scopus subject areas

  • Mathematics(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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