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Article: The effects of bed form roughness on total suspended load via the Lattice Boltzmann Method

TitleThe effects of bed form roughness on total suspended load via the Lattice Boltzmann Method
Authors
KeywordsBed form
Free surface
Lattice Boltzmann
Sediment transport
Suspended load
Issue Date2018
PublisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/apm
Citation
Applied Mathematical Modelling, 2018, v. 63, p. 591-610 How to Cite?
AbstractBed forms in natural rivers and man-made channels provide the dominant contribution to overall flow resistance and hence significantly affect sediment transport rate. Many laboratory experiments and field observations have been conducted on bed forms, and it was found that theoretical flat-bed assumptions do not give the correct estimation for the total suspended load (TSL). In this study, we present a systematic numerical investigation of turbulent open-channel flows over bed forms using the Lattice Boltzmann Method (LBM). A static Smagorinsky model is incorporated into LBM to account for turbulence, and the dynamic interface between fluid and air is captured by a free-surface model. The time-averaged flow velocity, turbulence intensity and Reynolds shear stress in LBM simulations show an excellent agreement with the available experimental data. In addition, the coherent flow structures induced by the bed forms qualitatively agree with previous numerical results from Large Eddy Simulations based the Navier–Stokes equations. We then proceed to investigate the effects of bed form roughness, quantified by the total friction factor fT, on sediment transport. It is found that the prediction of the TSL based on the theoretical flat-bed assumptions may lead to an overestimation of up to 30%, depending on the bed form roughness. In addition, the normalized TSL is linearly proportional to fT and nearly inversely proportional to the ratio of downward settling velocity and upward turbulence induced diffusion. Our work proposes a general law linking these quantities to estimate the TSL, which has the potential for a more efficient and accurate engineering design of man-made channels and improved river management.
Persistent Identifierhttp://hdl.handle.net/10722/259204
ISSN
2017 Impact Factor: 2.617
2015 SCImago Journal Rankings: 1.318
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorYang, GC-
dc.contributor.authorKwok, CY-
dc.contributor.authorSobral, YD-
dc.date.accessioned2018-09-03T04:03:07Z-
dc.date.available2018-09-03T04:03:07Z-
dc.date.issued2018-
dc.identifier.citationApplied Mathematical Modelling, 2018, v. 63, p. 591-610-
dc.identifier.issn0307-904X-
dc.identifier.urihttp://hdl.handle.net/10722/259204-
dc.description.abstractBed forms in natural rivers and man-made channels provide the dominant contribution to overall flow resistance and hence significantly affect sediment transport rate. Many laboratory experiments and field observations have been conducted on bed forms, and it was found that theoretical flat-bed assumptions do not give the correct estimation for the total suspended load (TSL). In this study, we present a systematic numerical investigation of turbulent open-channel flows over bed forms using the Lattice Boltzmann Method (LBM). A static Smagorinsky model is incorporated into LBM to account for turbulence, and the dynamic interface between fluid and air is captured by a free-surface model. The time-averaged flow velocity, turbulence intensity and Reynolds shear stress in LBM simulations show an excellent agreement with the available experimental data. In addition, the coherent flow structures induced by the bed forms qualitatively agree with previous numerical results from Large Eddy Simulations based the Navier–Stokes equations. We then proceed to investigate the effects of bed form roughness, quantified by the total friction factor fT, on sediment transport. It is found that the prediction of the TSL based on the theoretical flat-bed assumptions may lead to an overestimation of up to 30%, depending on the bed form roughness. In addition, the normalized TSL is linearly proportional to fT and nearly inversely proportional to the ratio of downward settling velocity and upward turbulence induced diffusion. Our work proposes a general law linking these quantities to estimate the TSL, which has the potential for a more efficient and accurate engineering design of man-made channels and improved river management.-
dc.languageeng-
dc.publisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/apm-
dc.relation.ispartofApplied Mathematical Modelling-
dc.subjectBed form-
dc.subjectFree surface-
dc.subjectLattice Boltzmann-
dc.subjectSediment transport-
dc.subjectSuspended load-
dc.titleThe effects of bed form roughness on total suspended load via the Lattice Boltzmann Method-
dc.typeArticle-
dc.identifier.emailKwok, CY: fkwok8@hku.hk-
dc.identifier.authorityKwok, CY=rp01344-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.apm.2018.07.011-
dc.identifier.scopuseid_2-s2.0-85050189183-
dc.identifier.hkuros289105-
dc.identifier.volume63-
dc.identifier.spage591-
dc.identifier.epage610-
dc.identifier.isiWOS:000444362800032-
dc.publisher.placeUnited States-

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