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Passive Shock Control Concept for Drag Reduction in Transonic Flow

Dietz, G. (2005) Passive Shock Control Concept for Drag Reduction in Transonic Flow. Journal of Aircraft, Vol. 42 (No. 3), Seiten 794-798.

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Kurzfassung

The operating principle of a novel passive shock control concept for drag reduction on swept wings called D-Strips is introduced, and results of a first experimental proof of concept are presented. Wind-tunnel experiments are conducted at transonic airspeeds using an airfoil VC-Opt (9.2% relative thickness) with forced boundary-layer transition. Schlieren pictures confirm the operating principle. Wake measurements demonstrate that, locally, in the wake of D-Strips the total drag increases. However, more globally, at spanwise locations away from these positions the total drag is measurably reduced if a sufficiently strong shockwave is present above the wing-suction-side surface. In contrast to passive control by ventilation, outside of the wake of the D-Strips a wave and viscous drag reduction and observed. Furthermore, the maximum lift tends to be increased by D-Strips suggesting that the buffet-onset limit is delayed. An application of D-Strips to a swept wing at cruise conditions can yield net aircraft drag reduction because the drag rise is limited to the D-Strips and its wake, but the shock-weakening effect and the drag reduction are distributed in the wide-splayed characteristics upstream of the shock front. The effectiveness of D-Strips is less sensitive to the location of the shock wave than control concepts like two-dimensional bumps, which are only effective at the design conditions. Another application of D-Strips that can be considered is the regions with a distinct shock, for example, between engines or in the wing-root region or at the inboard engine. However, there is a need for further investigations in order to optimize D-Strips and to quantify their impact on aircraft performance. Recent experimental results indicate that airscoop-type configurations might perform better as D-Strips than Velcro-type strips. Because D-Strips are easy to apply on existing wings, an application of D-Strips for retrofit is possible.

elib-URL des Eintrags:https://elib.dlr.de/14547/
Dokumentart:Zeitschriftenbeitrag
Zusätzliche Informationen: LIDO-Berichtsjahr=2005,
Titel:Passive Shock Control Concept for Drag Reduction in Transonic Flow
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Dietz, G.NICHT SPEZIFIZIERTNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:2005
Erschienen in:Journal of Aircraft
Referierte Publikation:Ja
Open Access:Nein
Gold Open Access:Nein
In SCOPUS:Nein
In ISI Web of Science:Ja
Band:Vol. 42
Seitenbereich:Seiten 794-798
Status:veröffentlicht
Stichwörter:flow control, transonic flow, drag reduction
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Luftfahrt
HGF - Programmthema:keine Zuordnung
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L ST - Starrflüglertechnologien
DLR - Teilgebiet (Projekt, Vorhaben):NICHT SPEZIFIZIERT
Standort: Göttingen
Institute & Einrichtungen:Institut für Aeroelastik
Hinterlegt von: Erdmann, Daniela
Hinterlegt am:16 Sep 2005
Letzte Änderung:14 Jan 2010 21:59

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