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Amplification and amplitude limitation of heave/pitch limit-cycle oscillations close to the transonic dip

Dietz, Guido and Schewe, Günter and Mai, Holger (2006) Amplification and amplitude limitation of heave/pitch limit-cycle oscillations close to the transonic dip. Journal of Fluids and Structures, 22 (4), pp. 505-527. Elsevier.

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Official URL: http://www.elsevier.com


Recent results from flutter experiments of the supercritical airfoil NLR 7301 at flow conditions close to the transonic dip are presented. The airfoil was mounted with two degrees-of-freedom in an adaptive solid-wall wind tunnel, and boundary-layer transition was tripped. Flutter boundaries exhibiting a transonic dip were determined and limit-cycle oscillations (LCOs) were measured. The local energy exchange between the fluid and the structure during LCOs is examined and leads to the following findings: at supercritical Mach numbers below that of the transonic-dip minimum the presence of a shock-wave and its dynamics destabilizes the aeroelastic system such that the decreasing branch of the transonic dip develops. At higher Mach numbers the shock-wave motion has a stabilizing effect such that the flutter boundary increases to higher flutter-speed indices with increasing Mach number. Amplified oscillations near this branch of the flutter boundary obtain energy from the flow mainly due to the dynamics of a trailing-edge flow separation. A slight nonlinear amplitude dependency of the shock motion and a possibly occurring boundary-layer separation cause the amplitude limitation of the observed LCOs. The impact of the findings on the numerical simulation of these phenomena is discussed.

Item URL in elib:https://elib.dlr.de/43722/
Document Type:Article
Title:Amplification and amplitude limitation of heave/pitch limit-cycle oscillations close to the transonic dip
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Dietz, GuidoInstitut für AeroelastikUNSPECIFIED
Schewe, GünterInstitut für AeroelastikUNSPECIFIED
Mai, HolgerInstitut für AeroelastikUNSPECIFIED
Date:May 2006
Journal or Publication Title:Journal of Fluids and Structures
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 505-527
Keywords:limit-cycle oscillations, transonic dip, flutter, supercritical airfoil
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research (old)
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flexible Aircraft (old)
Location: Göttingen
Institutes and Institutions:Institute of Aeroelasticity
Deposited By: Erdmann, Daniela
Deposited On:24 Jul 2006
Last Modified:27 Apr 2009 12:54

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