BiGlobal linear stability analysis on low-Re flow past an airfoil at high angle of attack

Handle URI:
http://hdl.handle.net/10754/604945
Title:
BiGlobal linear stability analysis on low-Re flow past an airfoil at high angle of attack
Authors:
Zhang, Wei ( 0000-0001-6323-1234 ) ; Samtaney, Ravi ( 0000-0002-4702-6473 )
Abstract:
We perform BiGlobal linear stability analysis on flow past a NACA0012 airfoil at 16° angle of attack and Reynolds number ranging from 400 to 1000. The steady-state two-dimensional base flows are computed using a well-tested finite difference code in combination with the selective frequency damping method. The base flow is characterized by two asymmetric recirculation bubbles downstream of the airfoil whose streamwise extent and the maximum reverse flow velocity increase with the Reynolds number. The stability analysis of the flow past the airfoil is carried out under very small spanwise wavenumber β = 10−4 to approximate the two-dimensional perturbation, and medium and large spanwise wavenumbers (β = 1–8) to account for the three-dimensional perturbation. Numerical results reveal that under small spanwise wavenumber, there are at most two oscillatory unstable modes corresponding to the near wake and far wake instabilities; the growth rate and frequency of the perturbation agree well with the two-dimensional direct numerical simulation results under all Reynolds numbers. For a larger spanwise wavenumber β = 1, there is only one oscillatory unstable mode associated with the wake instability at Re = 400 and 600, while at Re = 800 and 1000 there are two oscillatory unstable modes for the near wake and far wake instabilities, and one stationary unstable mode for the monotonically growing perturbation within the recirculation bubble via the centrifugal instability mechanism. All the unstable modes are weakened or even suppressed as the spanwise wavenumber further increases, among which the stationary mode persists until β = 4.
KAUST Department:
Mechanical Engineering Program; Physical Sciences and Engineering (PSE) Division
Citation:
BiGlobal linear stability analysis on low-Re flow past an airfoil at high angle of attack 2016, 28 (4):044105 Physics of Fluids
Publisher:
AIP Publishing
Journal:
Physics of Fluids
Issue Date:
4-Apr-2016
DOI:
10.1063/1.4945005
Type:
Article
ISSN:
1070-6631; 1089-7666
Sponsors:
The work was supported by the KAUST Office of Competitive Research Funds under Award No. URF/1/1394-01. The IBM Blue Gene/P Shaheen at KAUST was utilized for the simulations.
Additional Links:
http://scitation.aip.org/content/aip/journal/pof2/28/4/10.1063/1.4945005
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorZhang, Weien
dc.contributor.authorSamtaney, Ravien
dc.date.accessioned2016-04-10T13:37:57Zen
dc.date.available2016-04-10T13:37:57Zen
dc.date.issued2016-04-04en
dc.identifier.citationBiGlobal linear stability analysis on low-Re flow past an airfoil at high angle of attack 2016, 28 (4):044105 Physics of Fluidsen
dc.identifier.issn1070-6631en
dc.identifier.issn1089-7666en
dc.identifier.doi10.1063/1.4945005en
dc.identifier.urihttp://hdl.handle.net/10754/604945en
dc.description.abstractWe perform BiGlobal linear stability analysis on flow past a NACA0012 airfoil at 16° angle of attack and Reynolds number ranging from 400 to 1000. The steady-state two-dimensional base flows are computed using a well-tested finite difference code in combination with the selective frequency damping method. The base flow is characterized by two asymmetric recirculation bubbles downstream of the airfoil whose streamwise extent and the maximum reverse flow velocity increase with the Reynolds number. The stability analysis of the flow past the airfoil is carried out under very small spanwise wavenumber β = 10−4 to approximate the two-dimensional perturbation, and medium and large spanwise wavenumbers (β = 1–8) to account for the three-dimensional perturbation. Numerical results reveal that under small spanwise wavenumber, there are at most two oscillatory unstable modes corresponding to the near wake and far wake instabilities; the growth rate and frequency of the perturbation agree well with the two-dimensional direct numerical simulation results under all Reynolds numbers. For a larger spanwise wavenumber β = 1, there is only one oscillatory unstable mode associated with the wake instability at Re = 400 and 600, while at Re = 800 and 1000 there are two oscillatory unstable modes for the near wake and far wake instabilities, and one stationary unstable mode for the monotonically growing perturbation within the recirculation bubble via the centrifugal instability mechanism. All the unstable modes are weakened or even suppressed as the spanwise wavenumber further increases, among which the stationary mode persists until β = 4.en
dc.description.sponsorshipThe work was supported by the KAUST Office of Competitive Research Funds under Award No. URF/1/1394-01. The IBM Blue Gene/P Shaheen at KAUST was utilized for the simulations.en
dc.language.isoenen
dc.publisherAIP Publishingen
dc.relation.urlhttp://scitation.aip.org/content/aip/journal/pof2/28/4/10.1063/1.4945005en
dc.rightsArchived with thanks to Physics of Fluidsen
dc.titleBiGlobal linear stability analysis on low-Re flow past an airfoil at high angle of attacken
dc.typeArticleen
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalPhysics of Fluidsen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorZhang, Weien
kaust.authorSamtaney, Ravien
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