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Lifting-Surface Limit-Cycle Oscillations due to Transonic Flow

Dietz, Guido (2007) Lifting-Surface Limit-Cycle Oscillations due to Transonic Flow. Goldstein Lecture 2007, 14.11.2007, Manchester, UK (Europe).

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Abstract

Results from flutter and forced-oscillation wind-tunnel experiments at flow conditions close to the transonic dip are presented. 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 experimental findings at Reynolds-numbers of about 1.5 Mio. on the numerical simulation of these phenomena, and on future research at flight-relevant Reynolds-numbers is discussed.

Item URL in elib:https://elib.dlr.de/51913/
Document Type:Conference or Workshop Item (Speech)
Title:Lifting-Surface Limit-Cycle Oscillations due to Transonic Flow
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Dietz, GuidoUNSPECIFIEDUNSPECIFIED
Date:2007
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:limit-cycle oscillation, transonic dip, flutter, supercritical airfoil
Event Title:Goldstein Lecture 2007
Event Location:Manchester, UK (Europe)
Event Type:international Conference
Event Dates:14.11.2007
Organizer:Royal Aeronautical Society Manchester Branch / University of Manchester
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:20 Nov 2007
Last Modified:27 Apr 2009 14:29

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