The development of a new generation of aircraft with increased maneuverability, allowing operation at higher maximum pitch and roll rates and at higher angles of attack than currently possible, will require effective on-line systems to control the unsteady flowfield that develops over the wings. The control strategy must be based on a knowledge of the unsteady flow behaviour that is dominated by leading-edge separation and processes that occur subsequently, such as the formation of a dynamic-stall vortex. The effect on the unsteady surface pressures of controlled suction from a spanwise slot, located at 2 % chord in the suction surface of a two-dimensional NACA 0012 airfoil model, was examined in detail for a wide range of pitch rates with a constant velocity ramp motion. The experiments were conducted in the Andrew Fejer Wind Tunnel at the Illinois Institute of Technology's Fluid Dynamics Research Center. The optimum suction required to meet three different control objectives, suppresion of the dynamic-stall vortex, delaying detachment of the vortex from the airfoil surface, and maximizing the unsteady lift, was determined for different pitch rates and angles of attack. The pressure data were used to develop specifications for the flow state over the airfoil surface that would meet these objectives. Such specifications are necessary for the development of on-line flow management systems. A procedure was also developed to account for variations in suction and motion history.
Controlled leading-edge suction for management of unsteady separation over pitching airfoils
Geregelte Luftansaugung an der Flügeleintrittskante für das Management von instationären Strömungsablösevorgängen an der angestellten Tragflügeloberfläche
AIAA Journal ; 34 , 11 ; 2327-2336
1996
10 Seiten, 12 Bilder, 8 Quellen
Article (Journal)
English
Flugzeug , Leistungssteigerung , Manövrierfähigkeit , Luftströmung , Saugen , Spalt , Tragflügelumströmung , NACA-Profil , Anstellwinkel (Tragflügel) , Steuerungs- und Regelungssystem , Strömungsvorgang , instationäre Strömung , Abreißen der Strömung , Wirbelströmung , Strömungsgeschwindigkeit , Vergleichsmessung , Windkanal , Maximalleistung , Auftrieb , Druckverteilung , Online-Betrieb , Modellversuch , Wirbelbildung
Controlled Leading-Edge Suction for Management of Unsteady Separation over Pitching Airfoils
Online Contents | 1996
|Suppression of Dynamic-Stall Vortices over Pitching Airfoils by Leading-Edge Suction
Online Contents | 1994
|Suppression of dynamic-stall vortices over pitching airfoils by leading-edge suction
Tema Archive | 1994
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