Separation zone and morphodynamic evolution of coarse dunes using a process based 3D numerical model

Artemis Motamedi*, Hossein Afzalimehr, Gerald Zenz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Acoustic Doppler Velocimeters (ADV) experiments have been conducted over a fixed-dune to examine the effects of interacting dunes on the flow structure. The shape, dimensions and side angle of selected dunes were based upon previous empirical and field studies of dune morphology. Experiments were carried out on flow over a train of fixed 2D rough wall dunes in 12m flume. Dunes are developed in the height of 4 and 8 cm and in wavelength of 1m. This paper investigate the effect of lee angle (steep (>20°) and low (<10°) lee side angles) on separation zone and to study the effect of the dune bed roughness on turbulence structures and the length of separation zone calibrated RANS simulations was compared with experimental data. It is found that the models provide a good overall description measured by ADV. The separation zone also has a strong relation with lee angle and in the situation of low lee angle no flow separation was detected. Also increasing the dune height, roughness, water depth or velocity don't have an effective impact to separate the flow near the crest.

Original languageEnglish
Pages (from-to)380-388
Number of pages9
JournalEuropean Journal of Scientific Research
Volume62
Issue number3
Publication statusPublished - Oct 2011

Keywords

  • Dune
  • Dune Height
  • Lee Angle
  • Numerical Modeling
  • Reattachment point
  • Separation Zone

ASJC Scopus subject areas

  • Computer Science(all)
  • Mathematics(all)
  • Materials Science(all)
  • Agricultural and Biological Sciences(all)
  • Engineering(all)
  • Earth and Planetary Sciences(all)

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