DANS model for vegetated open channel flows

Chi Wai Li, Jiajia Li

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

ÂA novel Double Averaged Navier-Stokes equation model has been developed to simulate flows in vegetated open channels. Turbulence is modelled by the Spalart-Allmaras closure with a modified length scale, which is dependent on a zero-plane displacement parameter relating to the vegetation characteristics. The dispersive stress is modelled by a sub-length scale closure and the secondary current effect is modelled by a phenomenological expression. The simulation results show that the model is accurate for flows over vegetation with areal density ranging from 170 m-2 to 12,000 m-2. The computed dispersive stress and velocity dip are in reasonable agreement with the available experimental data. The effects of porosity and dispersive stress on the mean velocity and Reynolds stress are found to be minor. The model works well for gradually-varied flow over vegetation and predicts accurately the Manning roughness coefficient for flows over vegetation with low to high areal density.
Original languageEnglish
Pages (from-to)699-713
Number of pages15
JournalJournal of Hydraulic Research
Volume53
Issue number6
DOIs
Publication statusPublished - 2 Nov 2015

Keywords

  • DANS model
  • numerical model
  • open channel flow
  • turbulence closure
  • vegetated flow

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Water Science and Technology

Cite this