Wave-Drag Characteristics of an Over-the-Wing Nacelle Business-Jet Configuration, AIAA

This paper presents the wave-drag characteristics of an over-the-wing nacelle con guration. The ow over the wing is accelerated such that the aerodynamic interference between the nacelle and the wing is critical in the transonic ight regime. In general, locating nacelles over the wing causes anunfavorableaerodynamic interference and induces a strong shock wave,which results in a lower drag-divergenceMach number. If the nacelle is located at the optimumposition relative to the wing, however, the shock wave can be minimized, and drag divergence occurs at a Mach number higher than that for the clean-wing con guration. Theoretical analyses and experimental measurements demonstrate that a wave-drag reduction can be achieved by locating the nacelle front face near the shock-wave position on the wing. Nomenclature b = wing span, m (ft) CD = airplane drag coef cient.CD/M D 0:7 = airplane drag coef cient at M D 0:7 CDW = airplane wave-drag coef cient CL = airplane lift coef cient CM = airplane pitching-moment coef cient C p = pressure coef cient c = chord, m (ft) D = airplane drag, kgf (lbf) h = maximum height of nacelle, m (ft) L = airplane lift, kgf (lbf) M = freestreamMach number MDD = drag-divergenceMach number,Mach number where d.CD /=dM D 0:1 w = maximum width of nacelle, m (ft) X = chordwisedistance fromwing leading edge to nacelle front face,m (ft) x = chordwise distance from wing leading edge, m (ft) Y = spanwise distance from fuselage surface to nacelle inboard surface, m (ft) y = spanwise distance from fuselage centerline,m (ft) Z = vertical distance from wing upper surface to nacelle lower surface,m (ft) ´ = nondimensional span station, y=.b=2