Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Evolution of turbulence characteristics from straight to curved pipes
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.ORCID iD: 0000-0001-9627-5903
2013 (English)In: International Journal of Heat and Fluid Flow, ISSN 0142-727X, E-ISSN 1879-2278, Vol. 41, no SI, 16-26 p.Article in journal (Refereed) Published
Abstract [en]

Fully developed, statistically steady turbulent flow in straight and curved pipes at moderate Reynolds numbers is studied in detail using direct numerical simulations (DNS) based on a spectral element discretisation. After the validation of data and setup against existing DNS results, a comparative study of turbulent characteristics at different bulk Reynolds numbers Re-b = 5300 and 11,700, and various curvature parameters kappa = 0, 0.01, 0.1 is presented. In particular, complete Reynolds-stress budgets are reported for the first time. Instantaneous visualisations reveal partial relaminarisation along the inner surface of the curved pipe at the highest curvature, whereas developed turbulence is always maintained at the outer side. The mean flow shows asymmetry in the axial velocity profile and distinct Dean vortices as secondary motions. For strong curvature a distinct bulge appears close to the pipe centre, which has previously been observed in laminar and transitional curved pipes at lower Re-b only. On the other hand, mild curvature allows the interesting observation of a friction factor which is lower than in a straight pipe for the same flow rate. All statistical data, including mean profile, fluctuations and the Reynolds-stress budgets, is available for development and validation of turbulence models in curved geometries.

Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 41, no SI, 16-26 p.
Keyword [en]
Wall turbulence, Pipe flow, Curvature effects, Reynolds-stress budgets, Coiled tube
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:kth:diva-124983DOI: 10.1016/j.ijheatfluidflow.2013.03.005ISI: 000321078700003Scopus ID: 2-s2.0-84878568406OAI: oai:DiVA.org:kth-124983DiVA: diva2:638993
Conference
9th International Symposium on Engineering Turbulence Modelling and Measurements (ETMM), JUN 06-08, 2012, Thessaloniki, Greece
Funder
Swedish e‐Science Research Center
Note

QC 20130805

Available from: 2013-08-05 Created: 2013-08-02 Last updated: 2017-12-06Bibliographically approved
In thesis
1. Lagrangian Particles in Turbulence and Complex Geometries
Open this publication in new window or tab >>Lagrangian Particles in Turbulence and Complex Geometries
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Wall-dominated turbulent dispersed multiphase flows occur in a variety of industrial, biological and environmental applications. The complex nature of the  arrier and the dispersed phase is elevated to a higher level introducing geometrical complexities such as curved walls. Realising such flows and particulate phases poses challenging problems both from computational and also physical point of view. The present thesis tries to address some of these issues Lagrangian computational frame.

In the first step, turbulent flow in straight pipes is simulated by means ofdirect numerical simulation with a spectrally accurate code nek5000 to examine the Reynolds number effect on turbulent statistics. Adding the effect of the curvature to these canonical turbulent pipe flows generates Prandtl’s secondary motion of first kind. These configurations, as primary complex geometries in this study, are examined by means of statistical analysis to unfold the evolutionof turbulent characteristics from a straight pipe configuration. A fundamentally different Prandtl’s secondary motion of second kind is also put to test by means of adding the side-walls to a canonical turbulent channel flow and the evolution of various statistical quantities with varying the duct aspect ratios is discussed.

After having obtained a characterisation of the turbulent flow in the geometries of bent pipes and ducts, the dispersion of small heavy particles is modelled in the bent pipe by means of point particles which are one-way coupled to the flow. For this purpose a parallel Lagrangian Particle Tracking (LPT) scheme is implemented in the spectral-element code nek5000. Its numerical accuracy, parallel scalability and general performance in realistic situations are scrutinised in various situations. Also, the resulting particle fields are analysed, showing that even a small degree of geometrical curvature has a profound impact on the particle concentration maps.

For each of the aforementioned turbulent flow cases new and challenging questions have arisen to be addressed in the present and upcoming research works. Along with an improved understanding of the particle dispersion in the considered complex geometries, the current project is particularly intended to improve the numerical aspects of the current LPT module suitable for largescale computations.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. v, 41 p.
Series
TRITA-MEK, ISSN 0348-467X ; 2014:04
Keyword
Direct numerical simulation, wall turbulence, secondary motion
National Category
Fluid Mechanics and Acoustics
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-141909 (URN)978-91-7595-032-7 (ISBN)
Presentation
2014-03-11, E2, Linsdtedsvägen 3, KTH, Stockholm, 14:15 (English)
Opponent
Supervisors
Funder
Swedish e‐Science Research Center, 76304
Note

QC 20140226

Available from: 2014-02-26 Created: 2014-02-25 Last updated: 2014-02-26Bibliographically approved
2. Particle-laden Turbulent Wall-bounded Flows in Moderately Complex Geometries
Open this publication in new window or tab >>Particle-laden Turbulent Wall-bounded Flows in Moderately Complex Geometries
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Wall-bounded turbulent dispersed multiphase flows occur in a variety of industrial, biological and environmental applications. The complex nature of the carrier and the particulate phase is elevated to a higher level when introducing geometrical complexities such as curved walls. Realising such flows and dispersed phases poses challenging problems both from computational and also physical point of view. The present thesis addresses some of these issues by studying a coupled Eulerian–Lagrangian computational framework.

The content of the thesis addresses both turbulent wall flows and coupled particle motion. In the first part, turbulent flow in straight pipes is simulated by means of direct numerical simulation (DNS) with the spectrally accurate code nek5000  to examine the Reynolds-number effect on turbulence statistics. The effect of the curvature to these canonical turbulent pipe flows is then added to generate Prandtl’s secondary motion of first kind. These configurations, as primary complex geometries in this study, are examined by means of statistical analysis to unfold the evolution of turbulence characteristics from a straight pipe. A fundamentally different Prandtl’s secondary motion of the second kind is also put to test by adding side-walls to a canonical turbulent channel flow and analysing the evolution of various statistical quantities with varying the duct width-to-height aspect ratios.

Having obtained a characterisation of the turbulent flow in the geometries of bent pipes and ducts, the dispersion of small heavy particles is modelled in these configurations by means of point particles which are one-way coupled to the flow. For this purpose a parallel Lagrangian Particle Tracking (LPT) scheme is implemented in the spectral-element code nek5000 . Its numerical accuracy, parallel scalability and general performance in realistic situations is scrutinised. The analysis of the resulting particle fields shows that even a small amount of secondary motion has a profound impact on the particle phase dynamics and its concentration maps.

For each of the aforementioned turbulent flow cases new and challenging questions have arisen to be addressed in the present research works. The goal of extending understanding of the particle dispersion in turbulent bent pipes and rectangular ducts are also achieved.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2015. xii, 71 p.
Series
TRITA-MEK, ISSN 0348-467X ; 2015:09
Keyword
turbulent, complex geometry, particle
National Category
Fluid Mechanics and Acoustics
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-177310 (URN)978-91-7595-785-2 (ISBN)
Public defence
2015-12-04, F3, Lindstedtsvägen 26, KTH, Stockholm, 11:01 (English)
Opponent
Supervisors
Funder
Swedish e‐Science Research Center
Note

QC 20151118

Available from: 2015-11-18 Created: 2015-11-18 Last updated: 2015-11-18Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Schlatter, Philipp

Search in DiVA

By author/editor
Noorani, AzadEl Khoury, George. K.Schlatter, Philipp
By organisation
MechanicsLinné Flow Center, FLOW
In the same journal
International Journal of Heat and Fluid Flow
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 132 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf