Quadrant analysis of persistent spatial velocity perturbations over square-bar roughness

Dubravka Pokrajac, Lorna Jane Campbell, Vladimir Ivanovich Nikora, C. Manes, Ian Kenneth McEwan

Research output: Contribution to journalArticlepeer-review

75 Citations (Scopus)


We explore a new application of the quadrant method in the context of the double-averaged Navier-Stokes equations for studying open channel flow near rough beds. Quadrant analysis is applied to spatial disturbances of time-averaged velocity components, using the experimental data from flow over two-dimensional regular transverse square-bar roughness. The spatial velocity disturbances change periodically performing a full cycle over a single roughness element, so that the quadrant diagrams are regular closed orbits. A colour code is used to produce a quadrant map of the flow cross-section, which reveals contributions from each quadrant to the time-averaged momentum transfer.

Original languageEnglish
Pages (from-to)413-423
Number of pages11
JournalExperiments in Fluids
Issue number3
Publication statusPublished - Mar 2007


  • turbulent-boundary-layer
  • channel flow
  • wall
  • canopies
  • smooth
  • bed


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