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  • 1
    facet.materialart.
    Unbekannt
    In:  Other Sources
    Publikationsdatum: 2011-08-18
    Beschreibung: The potential of planform modification and hinge-line relocation to improve the thrust efficiency of vortex flaps was experimentally investigated on a 60-deg cropped delta wing model. Spanwise segmentation of the flap, together with chord-tailoring of the segments, allowed the vortex to be maintained on the outboard flap surfaces to higher angles of attack. In addition, location of the flap hinge aft of and underneath the wing leading edge generated substantial thrust from the vortex suction acting on the leading-edge lower surface. A combination of these beneficial effects allowed the flap/wing area to be reduced from 11.4 percent of the continuous flap to 6.3 percent of segmented flap, essentially without detriment to the incremental lift-to-drag ratio due to flap addition in the lift coefficient range 0.5-0.7 based on the basic wing area.
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Aircraft (ISSN 0021-8669); 20; 1062-106
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    facet.materialart.
    Unbekannt
    In:  Other Sources
    Publikationsdatum: 2011-08-16
    Beschreibung: The paper reviews the experimental data on the incipient separation characteristics of planar delta wings of 75 degree sharp leading edges, with full-span trailing edge flap deflected into the windward flow. The local Reynolds number range for these investigations covered laminar, transitional and turbulent conditions. It is shown that, while turbulent boundary layer data correlates with two dimensional results, in the laminar and transitional cases, there is a nearly parallel shift to higher flap angles for incipient separation.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal; 13; Oct. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2011-08-16
    Beschreibung: Severe flow separation in the 15:1 area-ratio, 38 deg total angle conical diffuser preceding the settling-chamber of an intermittent blowdown wind tunnel was eliminated by the use of a novel radial-splitter arrangement. As a consequence, the operating life of settling-chamber screens was greatly extended and test-section flow steadiness improved, with no penalty in the tunnel running time.
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Aircraft; 13; July 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2017-10-02
    Beschreibung: Recent progress in vortex-control applications for alleviating the adverse consequences of three dimensional separation and vortical interactions on slender body/swept wing configurations is reported. Examples include helical separation trip to alleviate the side force due to forebody vortex asymmetry; hinged strakes to avoid vortex breakdown effects; compartmentation of swept leading edge separation to delay the pitch-up instability; under wing vortex trip and vortex trip and vortex flaps for drag reduction at high lift; and an apex-flap trimmer to fully utilize the lift capability of trailing-edge flaps for take off and landing of delta wings. Experimental results on generic wind-tunnel models are presented to illustrate the vortex-management concepts involved and to indicate their potential for enhancing the subsonic aerodynamics of supersonic-cruise type vehicles.
    Schlagwort(e): AERODYNAMICS
    Materialart: AGARD Aerodyn. of Vortical Type Flows in Three Dimensions; 14 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2019-06-28
    Beschreibung: Results are presented of a subsonic experimental investigation of an apex flap concept on a 74 deg swept delta wing with trailing-edge flaps. The apex flap comprised approximately 6 percent of the wing area forward of a transverse hinge, allowing for upward and downward deflection angles from +40 deg to -20 deg. Upward deflection forces leading-edge vortex formation on the apex flap, resulting in an increased lift component on the apex area. The associated nose-up moment balances the nose-down moment due to trailing-edge flaps, resulting in sizeable increase in the trimmed lift coefficient particularly at low angles of attack. Nose-down apex deflection may be used to augment the pitch control for rapid recovery from high-alpha maneuvers. This report presents the balance data without analysis.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-166081 , NAS 1.26:166081
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2019-06-27
    Beschreibung: The multi-component airfoil program (Langley-MCARF) for attached flow is modified to accept the free vortex sheet separation-flow model program (Analytical Methods, Inc.-CLMAX). The viscous effects are incorporated into the calculation by representing the boundary layer displacement thickness with an appropriate source distribution. The separation flow model incorporated into MCARF was applied to single component airfoils. Calculated pressure distributions for angles of attack up to the stall are in close agreement with experimental measurements. Even at higher angles of attack beyond the stall, correct trends of separation, decrease in lift coefficients, and increase in pitching moment coefficients are predicted.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-159300
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2019-06-28
    Beschreibung: Low supersonic wave drag makes the thin highly swept delta wing the logical choice for use on aircraft designed for supersonic cruise. However, the high-lift maneuver capability of the aircraft is limited by severe induced-drag penalties attributed to loss of potential flow leading-edge suction. This drag increase may be alleviated through leading-edge flow control to recover lost aerodynamic thrust through either retention of attached leading-edge flow to higher angles of attack or exploitation of the increased suction potential of separation-induced vortex flow. A low-speed wind-tunnel investigation was undertaken to examine the high-lift devices such as fences, chordwise slots, pylon vortex generators, leading-edge vortex flaps, and sharp leading-edge extensions. The devices were tested individually and in combinations in an attempt to improve high-alpha drag performance with a minimum of low-alpha drag penalty. This report presents an analysis of the force, moment, and static pressure data obtained in angles of attack up to 23 deg, at Mach and Reynolds numbers of 0.16 and 3.85 x 10 to the 6th power per meter, respectively. The results indicate that all the devices produced drag and longitudinal/lateral stability improvements at high lift with, in most cases, minor drag penalties at low angles of attack.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-165923 , NAS 1.26:165923
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-28
    Beschreibung: An apparatus for alleviating high angle of attack side force on slender pointed cylindrical forebodies such as fighter aircraft, missiles and the like is described. A symmetrical pair of helical separation trips was employed to disrupt the leeside vortices normally attained. The symmetrical pair of trips starts at either a common point or at space points on the upper surface of the forebody and extends along separate helical paths along the circumference of the forebody.
    Schlagwort(e): AERODYNAMICS
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2019-06-28
    Beschreibung: The drag reduction devices selected for evaluation were the fence, slot, pylon-type vortex generator, and sharp leading-edge extension. These devices were tested on a 60 degree flatplate delta (with blunt leading edges) in the Langley Research Center 7- by 10-foot high-speed tunnel at low speed and to angles of attack of 28 degrees. Balance and static pressure measurements were taken. The results indicate that all the devices had significant drag reduction capability and improved longitudinal stability while a slight loss of lift and increased cruise drag occurred.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-165846
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2019-06-27
    Beschreibung: A new device was proposed for alleviating high angle-of-attack side force on slender, pointed forebodies. A symmetrical pair of separation strips in the form of helical ridges are applied to the forebody to disrupt the primary lee-side vortices and thereby avoid the instability that produces vortex asymmetry. Preliminary wind tunnel tests at Mach 0.3 and Reynolds no. 5,250,000 on a variety of forebody configurations and on a wing-body combination at angles of attack up to 56 degrees, demonstrated the effectiveness of the device.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-145361
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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