Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
A study of turbulent flow in large-scale porous media at high Reynolds numbers. Part I: numerical validation
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap. (Hydraulic Engineering)
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Vattendragsteknik.ORCID-id: 0000-0002-2342-2068
2016 (Engelska)Ingår i: Journal of Hydraulic Research, ISSN 0022-1686, E-ISSN 1814-2079, Vol. 54, nr 6, s. 663-677Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Analyses of turbulent flows through the downstream slopes of embankment dams are important for dam safety assessments, especially considering high-risk scenarios such as a sudden release of water due to internal erosion. Flow prediction is difficult in such situations due to coarseness of construction materials and high Reynolds numbers. The present study addresses this issue through comprehensive numerical modelling. The novelty of the proposed approach lies in a combination of large-scale experiments and three-dimensional numerical simulations, leading to a fully calibrated and validated model that is applicable to flows through cobble-sized materials (100–160 mm in diameter) at high Reynolds numbers (>104). Comparing the results of the standard turbulence models to data from the large-sale experiments, the renormalization group theory-based model yielded the smallest relative errors based on the hydraulic gradients. Considering the flow field, the turbulent shear stress increased by a factor of 17, and the time-averaged vorticities intensified by factors of 2, 6 and 10 for vorticities in the x-, y- and z-directions, respectively, due to the presence of cobbles.

Ort, förlag, år, upplaga, sidor
Taylor & Francis Group, 2016. Vol. 54, nr 6, s. 663-677
Nyckelord [en]
CFD validation, high Reynolds number turbulence, laboratory studies, numerical turbulence models, porous media flow
Nationell ämneskategori
Samhällsbyggnadsteknik
Forskningsämne
Byggvetenskap
Identifikatorer
URN: urn:nbn:se:kth:diva-193718DOI: 10.1080/00221686.2016.1211184ISI: 000386438300005Scopus ID: 2-s2.0-84982292500OAI: oai:DiVA.org:kth-193718DiVA, id: diva2:1033915
Anmärkning

QC 20161121

Tillgänglig från: 2016-10-10 Skapad: 2016-10-10 Senast uppdaterad: 2020-01-02Bibliografiskt granskad
Ingår i avhandling
1. Internal Erosion Phenomena in Embankment Dams: Throughflow and internal erosion mechanisms
Öppna denna publikation i ny flik eller fönster >>Internal Erosion Phenomena in Embankment Dams: Throughflow and internal erosion mechanisms
2016 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

 In this study, two major internal erosion initiation processes, suffusion and concentrated leak mechanisms, which lead to both defect formation in a dam’s body and its foundation and high throughflow in dams subjected to internal erosion were studied. This understanding has the potential to facilitate numerical modelling and expedite dam safety assessment studies. 

The throughflow properties of coarse rockfill material were studied by; analysing filed pump test data, performing extensive laboratory experiments with a large-scale apparatus and numerically simulating the three-dimensional flow through coarse rock materials, replicating the material used in the laboratory experiments.

Results from the tests demonstrate that the parameters of the nonlinear momentum equation of the flow depend on the Reynolds number for pore Reynolds numbers lower than 60000. 

Numerical studies were also carried out to conduct numerical experiments. By applying a Lagrangian particle tracking method, a model for estimating the lengths of the flow channels in the porous media was developed.  The shear forces exerted on the coarse particles in the porous media were found to be significantly dependent on the inertial forces of the flow.

Suffusion and concentrated leak mechanisms were also studied by means of laboratory experiments to develop a theoretical framework for continuum-based numerical modelling. An erosion apparatus was designed and constructed with the capability of applying hydraulic and mechanical loading. Results were then used to develop constitutive laws of the soil erosion as a function of the applied hydromechanical load for both suffusion and concentrated leak mechanisms. Both the initiation and mass removal rate of were found to be dependent on the soil in-situ stresses.

A three-dimensional electrical-resistivity-based tomography method was also adopted for the internal erosion apparatus and was found to be successful in visualising the porosity evolution due to suffusion.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2016. s. 74
Serie
TRITA-HYD ; 2016:4
Serie
ISSN, ISSN 1650-8602
Nyckelord
Internal erosion modelling in porous material; Constitutive law of erosion for closure of continuum-mechanics-based balance equations for numerical modelling; High Reynolds-number turbulent flow; Flow laws; Coarse rockfill material throughflow; Computational Fluid Dynamics.
Nationell ämneskategori
Geoteknik Vattenteknik
Forskningsämne
Byggvetenskap
Identifikatorer
urn:nbn:se:kth:diva-193627 (URN)978-91-7729-130-5 (ISBN)
Disputation
2016-11-04, Kollegiesalen, Brinellvägen 8, Stockholm, 09:00 (Engelska)
Opponent
Handledare
Anmärkning

QC 20161006

Tillgänglig från: 2016-10-06 Skapad: 2016-10-06 Senast uppdaterad: 2020-01-02Bibliografiskt granskad

Open Access i DiVA

omslag(2014 kB)38 nedladdningar
Filinformation
Filnamn COVER01.pdfFilstorlek 2014 kBChecksumma SHA-512
a1c7e33afeed946f65ca6d34c08bb43445a5c5b39846f9281a974e3980c9c9dfa674774307ba729a96dad3b07dba0d7fc20c56ba97a88e27414ac3d59bb215c0
Typ coverMimetyp application/pdf

Övriga länkar

Förlagets fulltextScopushttp://dx.doi.org/10.1080/00221686.2016.1211184

Sök vidare i DiVA

Av författaren/redaktören
Ferdos, FarzadDargahi, Bijan
Av organisationen
ByggvetenskapVattendragsteknik
I samma tidskrift
Journal of Hydraulic Research
Samhällsbyggnadsteknik

Sök vidare utanför DiVA

GoogleGoogle Scholar
Antalet nedladdningar är summan av nedladdningar för alla fulltexter. Det kan inkludera t.ex tidigare versioner som nu inte längre är tillgängliga.

doi
urn-nbn

Altmetricpoäng

doi
urn-nbn
Totalt: 317 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf