The near-field flow structure of a tip vortex behind a sweptback and tapered NACA 0015 wing was investigated and compared with a rectangular wing at the same lift force and Re=1.81x105. The tangential velocity decreased with the downstream distance while increased with the airfoil incidence. The core radius was about 3% of the root chord cr, regardless of the downstream distance and the angle of attack alpha for alpha < 8 deg. The core axial velocity was always wake-like. The core Gammac and total Gammao circulation of the tip vortex remained nearly constant up to x/cr = 3.5 and had a Gammac/Gammao ratio of 0.63. The total circulation of the tip vortex accounted for only about 40% of the bound root circulation Gammab. For a rectangular wing, the axial flow exhibited islands of wake- and jet-like velocity distributions with Gammac/Gammao = 0.75 and Gammao/Gammab = 0.70. For the sweptback and tapered wing tested, the inner region of the tip vortex flow exhibited a self-similar behavior for x/cr = 1.0. The lift force computed from the spanwise circulation distributions agreed well with the force-balance data. A large difference in the lift-induced drag was, however, observed between the wake integral method and the inviscid lifting-line theory.
Near-field tip vortex behind a swept wing model
Spitzenwirbel im nahen Nachstrom eines Pfeilflügelmodells
Experiments in Fluids ; 40 , 1 ; 141-155
2006
15 Seiten, 12 Bilder, 1 Tabelle, 26 Quellen
Aufsatz (Zeitschrift)
Englisch
Auftriebsbeiwert , Axialströmung , Geschwindigkeitsverteilung , NACA-Profil , Nachlaufströmung , Pfeilflügel , Radius , Strömungsgeschwindigkeitsmessung , Tangentialgeschwindigkeit , Widerstandsbeiwert , Windkanalprüfung , Wirbel (Strömung) , Wirbelkern , Zirkulation , rechteckige Form , Vergleichstest , Versuchsmodell
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