Enhanced understanding on incipient sedimentmotion and sediment suspension through oscillating-grid turbulence experiments

Research output: Contribution to journalArticle

Abstract

Sediment dynamics are usually described in terms of the studies developed under a steady uniform flow, where the hydrodynamic forces are taken those pertaining to the mean time-averaged flow speed. However, the inherent turbulence plays an important role and should be considered implicitly in describing the complexity of turbulence effects in geophysical phenomena. This paper reviews the implementation of isolated turbulence, generated by oscillating grid on two important sediment transport phenomena, i.e., incipient sediment motion and suspension. The generated quasi-isotropic, laterally homogenous turbulence (that is, at a distance further away from the grid) permits an in-depth investigation of the effect of turbulent fluctuations and brings new insights in understanding both phenomena. The critical Shields profile for the incipient sediment motion characterized using the second order of turbulence statistics is qualitatively similar to the Shields curve obtained under a steady uniform flow. In the suspension of particles, there is a two-way interaction between sediment and turbulence. High concentration of suspended particles changes the turbulence structure and the presence of coherent vortices changes the particle settling velocity, which subsequently alters the concentration within the suspension layer. The studies of turbulence on incipient sediment motion and particle suspension provide a better understanding of the underlying physics of sediment behavior at the near-bed region.

Original languageEnglish
Pages (from-to)882-894
Number of pages13
JournalJournal of Zhejiang University: Science A
Volume18
Issue number11
DOIs
Publication statusPublished - 1 Nov 2017

Fingerprint

Sediments
Turbulence
Experiments
Sediment transport
Vortex flow
Hydrodynamics
Physics
Statistics

Keywords

  • Incipient sediment motion
  • Oscillating-grid turbulence
  • Sediment resuspension

ASJC Scopus subject areas

  • Engineering(all)

Cite this

@article{3e1b581800054fdcb1f805d70fbe63f2,
title = "Enhanced understanding on incipient sedimentmotion and sediment suspension through oscillating-grid turbulence experiments",
abstract = "Sediment dynamics are usually described in terms of the studies developed under a steady uniform flow, where the hydrodynamic forces are taken those pertaining to the mean time-averaged flow speed. However, the inherent turbulence plays an important role and should be considered implicitly in describing the complexity of turbulence effects in geophysical phenomena. This paper reviews the implementation of isolated turbulence, generated by oscillating grid on two important sediment transport phenomena, i.e., incipient sediment motion and suspension. The generated quasi-isotropic, laterally homogenous turbulence (that is, at a distance further away from the grid) permits an in-depth investigation of the effect of turbulent fluctuations and brings new insights in understanding both phenomena. The critical Shields profile for the incipient sediment motion characterized using the second order of turbulence statistics is qualitatively similar to the Shields curve obtained under a steady uniform flow. In the suspension of particles, there is a two-way interaction between sediment and turbulence. High concentration of suspended particles changes the turbulence structure and the presence of coherent vortices changes the particle settling velocity, which subsequently alters the concentration within the suspension layer. The studies of turbulence on incipient sediment motion and particle suspension provide a better understanding of the underlying physics of sediment behavior at the near-bed region.",
keywords = "Incipient sediment motion, Oscillating-grid turbulence, Sediment resuspension",
author = "{Wan Mohtar}, {Wan Hanna Melini}",
year = "2017",
month = "11",
day = "1",
doi = "10.1631/jzus.A1600659",
language = "English",
volume = "18",
pages = "882--894",
journal = "Journal of Zhejinag University: Science",
issn = "1009-3095",
publisher = "Zhejiang University Press",
number = "11",

}

TY - JOUR

T1 - Enhanced understanding on incipient sedimentmotion and sediment suspension through oscillating-grid turbulence experiments

AU - Wan Mohtar, Wan Hanna Melini

PY - 2017/11/1

Y1 - 2017/11/1

N2 - Sediment dynamics are usually described in terms of the studies developed under a steady uniform flow, where the hydrodynamic forces are taken those pertaining to the mean time-averaged flow speed. However, the inherent turbulence plays an important role and should be considered implicitly in describing the complexity of turbulence effects in geophysical phenomena. This paper reviews the implementation of isolated turbulence, generated by oscillating grid on two important sediment transport phenomena, i.e., incipient sediment motion and suspension. The generated quasi-isotropic, laterally homogenous turbulence (that is, at a distance further away from the grid) permits an in-depth investigation of the effect of turbulent fluctuations and brings new insights in understanding both phenomena. The critical Shields profile for the incipient sediment motion characterized using the second order of turbulence statistics is qualitatively similar to the Shields curve obtained under a steady uniform flow. In the suspension of particles, there is a two-way interaction between sediment and turbulence. High concentration of suspended particles changes the turbulence structure and the presence of coherent vortices changes the particle settling velocity, which subsequently alters the concentration within the suspension layer. The studies of turbulence on incipient sediment motion and particle suspension provide a better understanding of the underlying physics of sediment behavior at the near-bed region.

AB - Sediment dynamics are usually described in terms of the studies developed under a steady uniform flow, where the hydrodynamic forces are taken those pertaining to the mean time-averaged flow speed. However, the inherent turbulence plays an important role and should be considered implicitly in describing the complexity of turbulence effects in geophysical phenomena. This paper reviews the implementation of isolated turbulence, generated by oscillating grid on two important sediment transport phenomena, i.e., incipient sediment motion and suspension. The generated quasi-isotropic, laterally homogenous turbulence (that is, at a distance further away from the grid) permits an in-depth investigation of the effect of turbulent fluctuations and brings new insights in understanding both phenomena. The critical Shields profile for the incipient sediment motion characterized using the second order of turbulence statistics is qualitatively similar to the Shields curve obtained under a steady uniform flow. In the suspension of particles, there is a two-way interaction between sediment and turbulence. High concentration of suspended particles changes the turbulence structure and the presence of coherent vortices changes the particle settling velocity, which subsequently alters the concentration within the suspension layer. The studies of turbulence on incipient sediment motion and particle suspension provide a better understanding of the underlying physics of sediment behavior at the near-bed region.

KW - Incipient sediment motion

KW - Oscillating-grid turbulence

KW - Sediment resuspension

UR - http://www.scopus.com/inward/record.url?scp=85033684424&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85033684424&partnerID=8YFLogxK

U2 - 10.1631/jzus.A1600659

DO - 10.1631/jzus.A1600659

M3 - Article

AN - SCOPUS:85033684424

VL - 18

SP - 882

EP - 894

JO - Journal of Zhejinag University: Science

JF - Journal of Zhejinag University: Science

SN - 1009-3095

IS - 11

ER -