The evolution of large-scale motions in turbulent pipe flow

Leo H.O. Hellström, Bharathram Ganapathisubramani, Alexander J. Smits

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


A dual-plane snapshot proper orthogonal decomposition (POD) analysis of turbulent pipe flow at a Reynolds number of 104 000 is presented. The high-speed particle image velocimetry data were simultaneously acquired in two planes, a cross-stream plane (2D-3C) and a streamwise plane (2D-2C) on the pipe centreline. The cross-stream plane analysis revealed large structures with a spatio-temporal extent of , where is the pipe radius. The temporal evolution of these large-scale structures is examined using the time-shifted correlation of the cross-stream snapshot POD coefficients, identifying the low-energy intermediate modes responsible for the transition between the large-scale modes. By conditionally averaging based on the occurrence/intensity of a given cross-stream snapshot POD mode, a complex structure consisting of wall-attached and -detached large-scale structures is shown to be associated with the most energetic modes. There is a pseudo-alignment of these large structures, which together create structures with a spatio-temporal extent of approximately , which appears to explain the formation of the very-large-scale motions previously observed in pipe flow.

Original languageEnglish (US)
Pages (from-to)701-715
Number of pages15
JournalJournal of Fluid Mechanics
StatePublished - Aug 19 2015

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics


  • turbulent boundary layers
  • turbulent flows


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