Turbulence characteristics of flow over a cobble bed

Fabian Lopez, Chad Dunn, Marcelo Horacio Garcia

Research output: Contribution to conferencePaperpeer-review


Experiments are carried out on uniform, turbulent open-channel flow over large roughness elements (cobbles) using recently available technology (Acoustic Doppler Velocimetry) in order to characterize the turbulence structure and the role played by coherent events, for a given range of Reynolds and Froude numbers. Large gradients of vertical turbulent kinetic energy were observed offering a plausible explanation for the lack of fit of the log law. Conditional quadrant-technique shows the flow depth divided into two regions of marked different structure with ejections and sweeps making the major contributions to the Reynolds stress above and within the cobbles, respectively. One of the main effects of the roughness elements has been found to be in the way by which mean-flow energy is transferred towards the turbulent fluctuations in different flow regions.

Original languageEnglish (US)
Number of pages5
StatePublished - 1995
EventProceedings of the 1st International Conference on Water Resources. Part 1 (of 2) - San Antonio, TX, USA
Duration: Aug 14 1995Aug 18 1995


OtherProceedings of the 1st International Conference on Water Resources. Part 1 (of 2)
CitySan Antonio, TX, USA

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Environmental Science(all)


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