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Investigation of the unsteady flow field inside a leading edge slat cove

Käpernick, Kristian und Koop, Lars und Ehrenfried, Klaus (2005) Investigation of the unsteady flow field inside a leading edge slat cove. In: 11th AIAA/CEAS Aeroacoustics Conference, Conference proceedings, Seiten 1-16. American Institute of Aeronautics and Astronautics. 11th AIAA/CEAS Aeroacoustics Conference, Monterey, California, USA, 23 -25 May 2005, 2005-05-23 - 2005-05-25, Monterey, CA (USA). ISBN 1-5634-7761-0.

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Kurzfassung

An experimental investigation of the unsteady flow field inside a slat cove was performed to identify possible sound source generation mechanisms. Tests were carried out on a swept constant chord half-model with a stored chord length of 0.45 m. Experiments were conducted in the 2.0 m x 1.4 m wind tunnel facility of the Technical University of Berlin at an angle of attack of 4°, 8°, 12° and 16° and free stream velocities ranging from 20 m/s up to 35 m/s. The slat cove flow field was investigated by Particle Image Velocimitry (PIV) while the radiated sound was recorded with a single microphone. Both measurements were conducted in a synchronized manner to allow a correlation between the flow field and the sound pressure. An inspection of instantaneous PIV images shows a free shear layer emanating from the slat cusp with discrete vortices further downstream. The shear layer impinges on the inner slat surface and some vortices get trapped inside the recirculation area. Based on a simplified form of the Lighthill-equation sound source terms are calculated. A dipole type sound source distribution is found along the shear layer with decreasing strength further down the shear layer. In addition the vortex shedding frequency of the shear layer vortices is estimated from the instantaneous PIV data. The shedding frequency has a Poisson-like probability distribution with center frequencies ranging from 4 kHz to 10 kHz. The mean shedding frequency scales linearly with the mean velocity of the shear layer. It could not clearly be verified that vortex shedding from the slat cusp is the cause for low frequency broad band noise. For a particular configuration several discrete tones can be observed. It is suspected that this tonal noise originates from the junction between the slat and the fuselage.

Dokumentart:Konferenzbeitrag (Vortrag, Paper)
Zusätzliche Informationen: LIDO-Berichtsjahr=2005, monograph_id=AIAA 2005-2813,
Titel:Investigation of the unsteady flow field inside a leading edge slat cove
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Käpernick, KristianNICHT SPEZIFIZIERT
Koop, LarsNICHT SPEZIFIZIERT
Ehrenfried, KlausNICHT SPEZIFIZIERT
Datum:2005
Erschienen in:11th AIAA/CEAS Aeroacoustics Conference
Referierte Publikation:Nein
In SCOPUS:Nein
In ISI Web of Science:Nein
Band:Conference proceedings
Seitenbereich:Seiten 1-16
Herausgeber:
HerausgeberInstitution und/oder E-Mail-Adresse der Herausgeber
AIAA, NICHT SPEZIFIZIERT
Verlag:American Institute of Aeronautics and Astronautics
Name der Reihe:CD-ROM
ISBN:1-5634-7761-0
Status:veröffentlicht
Stichwörter:PIV, Slat cove, noise source mechanisms, swept wing, airframe noise
Veranstaltungstitel:11th AIAA/CEAS Aeroacoustics Conference, Monterey, California, USA, 23 -25 May 2005
Veranstaltungsort:Monterey, CA (USA)
Veranstaltungsart:internationale Konferenz
Veranstaltungsdatum:2005-05-23 - 2005-05-25
Veranstalter :AIAA
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Luftfahrt
HGF - Programmthema:Starrflügler
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L AR - Starrflüglerforschung
DLR - Teilgebiet (Projekt, Vorhaben):L - Flugphysik
Standort: Göttingen
Institute & Einrichtungen:Institut für Aerodynamik und Strömungstechnik > Hubschrauber
Institut für Aerodynamik und Strömungstechnik > Experimentelle Verfahren
Hinterlegt von: Ilka Micknaus
Hinterlegt am:27 Jan 2006
Letzte Änderung:14 Jan 2010 19:51

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