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Spectral-element simulations of separated turbulent internal flows
KTH, School of Engineering Sciences (SCI), Mechanics. (Prof. Dan S. Henningson)
2009 (English)Licentiate thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Stockholm: US-AB , 2009. , vii, 32 p.
Series
Trita-MEK, ISSN 0348-467X ; 2009:13
Keyword [en]
spectral element method, direct numerical simulations (DNS), turbulence, dealiasing, three-dimensional separation, massively parallel simulations
Identifiers
URN: urn:nbn:se:kth:diva-11643ISBN: 978-91-7415-506-8 (print)OAI: oai:DiVA.org:kth-11643DiVA: diva2:278603
Presentation
2009-12-15, E3, Osquars Backe 14, Stockholm, 10:15 (English)
Opponent
Supervisors
Note
QC 20101105Available from: 2009-11-27 Created: 2009-11-27 Last updated: 2010-11-05Bibliographically approved
List of papers
1. The Spectral-Element and Pseudo-Spectral Methods: A Comparative Study
Open this publication in new window or tab >>The Spectral-Element and Pseudo-Spectral Methods: A Comparative Study
2011 (English)In: Spectral and High Order Methods for Partial Differential Equations: Selected papers from the ICOSAHOM '09 conference, June 22-26, Trondheim, Norway / [ed] Jan S. Hesthaven; Einar M. Rønquist, Springer , 2011, 1, 459-467 p.Chapter in book (Other academic)
Abstract [en]

Turbulent and transitional channel flow simulations have been performed in order to assess the differences concerning speed and accuracy in the pseudo-spectral code simson and the spectral-element code nek5000. The results indicate that the pseudo-spectral code is 4–6 times faster than the spectral-element code in fully turbulent channel flow simulations, and up to 10–20 times faster when taking into account the more severe CFL restriction in the spectral-element code. No particular difference concerning accuracy could be noticed either in the turbulent nor the transitional cases, except for the pressure fluctuations at the wall which converge slower for the spectral-element code.

Place, publisher, year, edition, pages
Springer, 2011 Edition: 1
Series
Lecture Notes in Computational Science and Engineering, ISSN 1439-7358 ; 76
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25929 (URN)10.1007/978-3-642-15337-2_44 (DOI)2-s2.0-78651552857 (Scopus ID)978-3-642-15336-5 (ISBN)
Note
QC 20101105Available from: 2010-11-05 Created: 2010-11-05 Last updated: 2011-12-06Bibliographically approved
2. Stabilization of the Spectral-Element Method in Turbulent Flow Simulations
Open this publication in new window or tab >>Stabilization of the Spectral-Element Method in Turbulent Flow Simulations
2011 (English)In: Spectral and High Order Methods for Partial Differential Equations: Selected papers from the ICOSAHOM '09 conference, June 22-26, Trondheim, Norway, Springer , 2011, 1, 449-458 p.Conference paper, Published paper (Refereed)
Abstract [en]

The effect of over-integration and filter-based stabilization in the spectral-element method is investigated. There is a need to stabilize the SEM for flow problems involving non-smooth solutions, e.g., turbulent flow simulations. In model problems such as the Burgers’ equation (similar to Kirby and Karniadakis, J. Comput. Phys. 191:249–264, 2003) and the scalar transport equation together with full Navier–Stokes simulations it is noticed that over-integration with the full 3/2-rule is not required for stability. The first additional over-integration nodes are the most efficient to remove aliasing errors. Alternatively, filter-based stabilization can in many cases alone help to stabilize the computation.

Place, publisher, year, edition, pages
Springer, 2011 Edition: 1
Series
Lecture Notes in Computational Science and Engineering, ISSN 1439-7358 ; 76
Keyword
Aliasing error, Burgers' equations, Filter-based, Flow problems, Model problems, Navier Stokes simulation, Non-smooth, Scalar transport equation, SEM, Spectral element method
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25931 (URN)10.1007/978-3-642-15337-2_43 (DOI)2-s2.0-78651526122 (Scopus ID)978-3-642-15336-5 (ISBN)
Conference
8th International Conference on Spectral and High Order Methods, ICOSAHOM'09; Trondheim; Norway; 22 June 2009 through 26 June 2009
Note

QC 20101105

Available from: 2010-11-05 Created: 2010-11-05 Last updated: 2013-11-06Bibliographically approved
3. Large-Eddy Simulation of Turbulent Flow in a Plane Asymmetric Diffuser by the Spectral-Element Method
Open this publication in new window or tab >>Large-Eddy Simulation of Turbulent Flow in a Plane Asymmetric Diffuser by the Spectral-Element Method
2010 (English)In: Direct and Large-Eddy Simulation VII: Proceedings of the Seventh International ERCOFTAC Workshop on Direct and Large-Eddy Simulation, held at the University of Trieste, September 8-10, 2008 / [ed] Vincenzo Armenio, Bernard Geurts; Jochen Fröhlich, Springer , 2010, 1, 193-199 p.Chapter in book (Other academic)
Abstract [en]

LES and no-model LES (coarse-grid DNS) have been performed of turbulent flow in a plane asymmetric diffuser by the Spectral-Element Method (SEM). Mean profile and turbulent stresses compare well to LES results from Herbst e, however the SEM generally predicts a later (i.e. further downstream) separation. It can be concluded that the use of a high-order method is advantageous for flows featuring pressure-induced separation.

Place, publisher, year, edition, pages
Springer, 2010 Edition: 1
Series
ERCOFTAC Series, ISSN 1382-4309 ; Vol 13, Part 2
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25932 (URN)10.1007/978-90-481-3652-0_29 (DOI)000306194300029 ()978-90-481-3651-3 (ISBN)
Note

QC 20101105

Available from: 2010-11-05 Created: 2010-11-05 Last updated: 2013-05-06Bibliographically approved
4. Generation of accurate turbulent inflow conditions by efficient trip-forcing
Open this publication in new window or tab >>Generation of accurate turbulent inflow conditions by efficient trip-forcing
(English)Report (Other academic)
Place, publisher, year, edition, pages
Stockholm: KTH
Series
Internal Report; KTH Mechanics
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25933 (URN)
Note
QC 20101105Available from: 2010-11-05 Created: 2010-11-05 Last updated: 2010-11-05Bibliographically approved
5. Direct numerical simulation of separated flow in a three-dimensional diffuser
Open this publication in new window or tab >>Direct numerical simulation of separated flow in a three-dimensional diffuser
2010 (English)In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 650, 307-318 p.Article in journal (Refereed) Published
Abstract [en]

A direct numerical simulation (DNS) of turbulent flow in a three-dimensional diffuser at Re = 10 000 (based on bulk velocity and inflow-duct height) was performed with a massively parallel high-order spectral element method running on up to 32 768 processors. Accurate inflow condition is ensured through unsteady trip forcing and a long development section. Mean flow results are in good agreement with experimental data by Cherry et al. (Intl J. Heat Fluid Flow, vol. 29, 2008, pp. 803-811), in particular the separated region starting from one corner and gradually spreading to the top expanding diffuser wall. It is found that the corner vortices induced by the secondary flow in the duct persist into the diffuser, where they give rise to a dominant low-speed streak, due to a similar mechanism as the 'lift-up effect' in transitional shear flows, thus governing the separation behaviour. Well-resolved simulations of complex turbulent flows are thus possible even at realistic Reynolds numbers, providing accurate and detailed information about the flow physics. The available Reynolds stress budgets provide valuable references for future development of turbulence models.

Keyword
Bulk velocity, Complex turbulent flows, Experimental data, Flow physics, Heat fluid flow, High-order, Inflow conditions, Mean flow, Reynolds stress, Separated flows, Separated region, Separation behaviour, Spectral element method
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25925 (URN)10.1017/S0022112010000558 (DOI)000278212500011 ()2-s2.0-77952428627 (Scopus ID)
Note
QC 20101105Available from: 2010-11-05 Created: 2010-11-05 Last updated: 2017-12-12Bibliographically approved
6. Performance of the spectral-element code Nek5000 in turbulent and transitional channel flow simulations
Open this publication in new window or tab >>Performance of the spectral-element code Nek5000 in turbulent and transitional channel flow simulations
2009 (English)Report (Other academic)
Place, publisher, year, edition, pages
Stockholm: KTH, 2009
Series
Internal Report; KTH Mechanics
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25934 (URN)
Note

QC 20101105

Available from: 2010-11-05 Created: 2010-11-05 Last updated: 2016-05-11Bibliographically approved

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Citation style
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