The effectiveness of a new version of an elliptic cross-section tip in controlling the asymmetry of the vortex wake of an axisymmetric body at angle of attack has been studied. The elliptic cross sections were generated using two sixth-degree polynomials such that the tip radius, slope, and curvature would match those of a right circular cone at the point where the polynomial became tangent to a cone generator. The tip was found to be effective in varying the vortex wake geometry of a right circular cone at large angle of attack. The measured side force coefficient varied smoothly with tip roll angle for the two lowest angles of attack studied and exhibited square-wave and more undesirable variations for the larger angles of attack studied. These square-wave and peak, reduction-in-magnitude, and change-in-sign variations were caused by vortex breakaway, which allowed vortex crossover to occur. Ahead of vortex breakdaway, the elliptic cross-section tip yielded smooth variations of vortex wake asymmetry with tip roll angle, indicating that the tip would possibly be a feasible control device for high-performance fighter aircraft at high angle of attack.
Elliptic tip effects on the vortex wake of an axisymmetric body at incidence
Auswirkungen der konischen Flugzeugnase mit elliptischem Querschnitt auf die Wirbelnachströmung eines angestellten achsensymmetrischen Flugkörpers
AIAA Journal ; 32 , 7 ; 1437-1445
1994
9 Seiten, 16 Bilder, 29 Quellen
Article (Journal)
English
Militärflugzeug , Flugkörper , Seitenkraft , Steuerung , Querschnitt , Wirbelströmung , Anstellwinkel (Tragflügel) , Ellipse , Krümmung , Radius , Konizität , Wirbelablösung , Steuereinrichtung , Vergleichsmessung , Kraftmessung , Reynolds-Zahl , sichtbare Strömung , Wirbelstraße , Bahnkurve , Rollwinkel
Elliptic Tip Effects on the Vortex Wake of an Axisymmetric Body at Incidence
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