Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • 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
Unsteady aerodynamic effects in small-amplitude pitch oscillations of an airfoil
KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. KTH, Centres, SeRC - Swedish e-Science Research Centre.
KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, Centres, SeRC - Swedish e-Science Research Centre.
KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. KTH, Centres, SeRC - Swedish e-Science Research Centre. Swedish e-Science Research Center (SeRC).
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
National Category
Fluid Mechanics and Acoustics
Research subject
Engineering Mechanics
Identifiers
URN: urn:nbn:se:kth:diva-217976ISRN: KTH/MEK/TR-17/15-SEOAI: oai:DiVA.org:kth-217976DiVA, id: diva2:1158479
Note

QC 20171121

Available from: 2017-11-20 Created: 2017-11-20 Last updated: 2017-11-21Bibliographically approved
In thesis
1. Boundary layers over wing sections
Open this publication in new window or tab >>Boundary layers over wing sections
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The understanding of developing boundary layers over wings is an important topic from the perspective of industrial applications. An increased understanding would be consequential not only for achieving higher fuel efficiency but also in the design of aircraft control strategies. With these aims in mind, the current work aims to further the understanding of developing boundary layer over wingsections. The study is performed with two particular perspectives in mind -unsteady aerodynamic effects in a pitching airfoil and turbulent boundary layerstructure in non-equilibrium boundary layers over a stationary airfoil.The boundary layer evolution in unsteady natural laminar flow airfoils undergoing small-amplitude pitch-oscillations is investigated. For high Reynolds numbers the origins of the non-linear unsteady aerodynamic response of laminar airfoils is explained on the basis of quasi-steady assumptions. Temporal nonlinearitiesin aerodynamic forces are shown to be inherently linked to thenon-linearities of static aerodynamic force coefficients and that a simple phaselagconcept can model the observed non-linear unsteady response. On the other hand at lower Reynolds numbers, when there exists an unstable leading edgelaminar separation bubble, the unsteady response is dynamically rich and changes in boundary layer characteristics can be abrupt. Such quasi-steadyphase-lag concepts are no longer appropriate to explain the unsteady flow physics in such a case. For the case of stationary airfoils, flow statistics for flow around an airfoil at two different Reynolds numbers are compared to assess Reynolds number effects in non-equilibrium flows. Pressure gradient effects found to be stronger at low Reynolds numbers, leading to higher energy in the larger structures present  in the outer part of the turbulent boundary layer.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. p. 25
Series
TRITA-MEK, ISSN 0348-467X ; 2017:15
National Category
Fluid Mechanics and Acoustics Aerospace Engineering
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-217984 (URN)978-91-7729-591-4 (ISBN)
Presentation
2017-12-13, D3, Lindstedtsvägen 5, KTH, Stockholm, 15:15 (English)
Opponent
Supervisors
Note

QC 20171121

Available from: 2017-11-21 Created: 2017-11-20 Last updated: 2017-11-22Bibliographically approved

Open Access in DiVA

negi_unsteady_aerodynamic_effects_pitching_airfoil.pdf(15219 kB)76 downloads
File information
File name FULLTEXT01.pdfFile size 15219 kBChecksum SHA-512
04e4d4948ea40eb143554bcfb649faac156d506cc600c8c6f46f9c53bbeeaaf28104f39b5259ab1fd239c20bffd5ecbff20a87fb483cc0a8f0dfadaae4768fad
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Negi, PrabalVinuesa, RicardoHanifi, ArdeshirHenningson, Dan
By organisation
Stability, Transition and ControlLinné Flow Center, FLOWSeRC - Swedish e-Science Research Centre
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar
Total: 76 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 84 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • 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