Numerical study of the primary instability in a separated boundary layer transition under elevated free-stream turbulence

Hdl Handle:
http://hdl.handle.net/10545/620640
Title:
Numerical study of the primary instability in a separated boundary layer transition under elevated free-stream turbulence
Authors:
Langari, Mostafa; Yang, Zhiyin ( 0000-0002-6629-1360 )
Abstract:
Numerical studies of laminar-to-turbulent transition in a separation bubble subjected to two free-stream turbulence levels (FST) have been performed using Large-Eddy Simulation (LES). Separation of the laminar boundary layer occurs at a curvature change over a plate with a semi-circular leading edge at Re = 3450 based on the plate thickness and the uniform inlet velocity. A numerical trip is used to produce the targeted free-stream turbulence levels and the decay of free-stream turbulence is well predicted. A dynamic sub-grid-scale model is employed in the current study and a good agreement has been obtained between the LES results and the experimental data. Detailed analysis of the LES data has been carried out to investigate the primary instability mechanism. The flow visualisations and spectral analysis of the separated shear layer reveal that the 2D Kelvin-Helmholtz instability mode, well known to occur at low FST levels, is bypassed at higher levels leading to earlier breakdown to turbulence.
Affiliation:
University of Sussex, Brighton, UK; University of Derby, UK
Citation:
Langari, M., Yang, Z. 'Numerical study of the primary instability in a separated boundary layer transition under elevated free-stream turbulence' 2013, 25 (7):074106 Physics of Fluids
Publisher:
AIP Publishing
Journal:
Physics of Fluids
Issue Date:
25-Jul-2013
URI:
http://hdl.handle.net/10545/620640
DOI:
10.1063/1.4816291
Additional Links:
http://scitation.aip.org/content/aip/journal/pof2/25/7/10.1063/1.4816291; http://scitation.aip.org/content/aip/journal/pof2;jsessionid=q_e7ESabqj2dVx1vpVPzDNL2.x-aip-live-02
Type:
Article
Language:
en
ISSN:
10706631
Appears in Collections:
Department of Mechanical Engineering & the Built Environment

Full metadata record

DC FieldValue Language
dc.contributor.authorLangari, Mostafaen
dc.contributor.authorYang, Zhiyinen
dc.date.accessioned2016-10-17T19:48:02Z-
dc.date.available2016-10-17T19:48:02Z-
dc.date.issued2013-07-25-
dc.identifier.citationLangari, M., Yang, Z. 'Numerical study of the primary instability in a separated boundary layer transition under elevated free-stream turbulence' 2013, 25 (7):074106 Physics of Fluidsen
dc.identifier.issn10706631-
dc.identifier.doi10.1063/1.4816291-
dc.identifier.urihttp://hdl.handle.net/10545/620640-
dc.description.abstractNumerical studies of laminar-to-turbulent transition in a separation bubble subjected to two free-stream turbulence levels (FST) have been performed using Large-Eddy Simulation (LES). Separation of the laminar boundary layer occurs at a curvature change over a plate with a semi-circular leading edge at Re = 3450 based on the plate thickness and the uniform inlet velocity. A numerical trip is used to produce the targeted free-stream turbulence levels and the decay of free-stream turbulence is well predicted. A dynamic sub-grid-scale model is employed in the current study and a good agreement has been obtained between the LES results and the experimental data. Detailed analysis of the LES data has been carried out to investigate the primary instability mechanism. The flow visualisations and spectral analysis of the separated shear layer reveal that the 2D Kelvin-Helmholtz instability mode, well known to occur at low FST levels, is bypassed at higher levels leading to earlier breakdown to turbulence.en
dc.language.isoenen
dc.publisherAIP Publishingen
dc.relation.urlhttp://scitation.aip.org/content/aip/journal/pof2/25/7/10.1063/1.4816291en
dc.relation.urlhttp://scitation.aip.org/content/aip/journal/pof2;jsessionid=q_e7ESabqj2dVx1vpVPzDNL2.x-aip-live-02en
dc.rightsArchived with thanks to Physics of Fluidsen
dc.subjectInstabilityen
dc.subjectSeparated boundary layeren
dc.titleNumerical study of the primary instability in a separated boundary layer transition under elevated free-stream turbulenceen
dc.typeArticleen
dc.contributor.departmentUniversity of Sussex, Brighton, UKen
dc.contributor.departmentUniversity of Derby, UKen
dc.identifier.journalPhysics of Fluidsen
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