Experimental and Numerical Studies of Geometry Effects on UCAV's Aerodynamics

Huang, Xing; Mébarki, Youssef; Benmeddour, Ali; Brown, Todd

doi:10.2514/6.2004-403

Cited by 7 publications

(2 citation statements)

References 2 publications

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“…Strong Reynolds number influence [29] for Λ=55° wings, even with sharp leading-edges, was noted near the stall angle, with earlier stall as the Reynolds number is increased in the range of Re=0.38 to 2.2*10 6 . As will be discussed later, there is a direct relation between flow reattachment and stall; this indicates that the Reynolds number has possible effect on reattachment.…”

Section: Aerodynamic Forcesmentioning

confidence: 90%

Unsteady aerodynamics of nonslender delta wings

Gursul

Gordnier

Visbal

2005

Progress in Aerospace Sciences

271

138

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Unsteady aerodynamics of nonslender delta wings, covering topics of shear layer instabilities, structure of nonslender vortices, breakdown, maneuvering wings, and fluid/structure interactions, are reviewed in this paper. Vortical flows develop at very low angles of attack, and form close to the wing surface. This results in strong interactions with the upper-surface boundary layer and in a pronounced dependence of the flow structure on Reynolds number. Vortex breakdown is observed to be much less abrupt compared to breakdown over slender wings. This results in challenges for the precise determination of vortex breakdown location and the interpretation of flow visualizations. One of the distinct features of nonslender wings is the location of the primary attachment zone outboard of the symmetry plane. Reattachment location correlates with the wing stall process and increased buffeting. Dramatic fluid/structure interactions emerge with increasing wing flexibility and result in substantial lift enhancement in the post-stall region. This recently discovered phenomenon appears to be a feature of nonslender wings. Rigid delta wings undergoing small amplitude oscillations in the post-stall region exhibit many similarities to flexible wings, including reattachment and reformation of the leading-edge vortices. Unusual self-excited roll oscillations have also been observed for free-to-roll nonslender wings.

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Section: Aerodynamic Forcesmentioning

confidence: 90%

Unsteady aerodynamics of nonslender delta wings

Gursul

Gordnier

Visbal

2005

Progress in Aerospace Sciences

271

138

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“…The bursting occurs now near the apex. 18 on 65 o swept delta wings. As far as the onset of the primary separation is concerned, in the α-range tested here the primary separation on all three models was observed to start at the apex and not at some distance downstream from this point.…”

Section: Models and Flow Facility Used For Balance Measurementsmentioning

confidence: 99%

Effects of Leading-Edge Radius on Aerodynamic Characteristics of 50º Delta Wings

Verhaagen

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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The study focuses on the effects of the leading-edge radius on the flow over 50 o swept delta wing models. Three models were tested, one model having a sharp leading edge and the other two having a semi-circular leading edge of different radius. The vortical flow on and off the surface of the models was investigated using an oil-flow visualization and a Stereo Particle Image Velocimetry (SPIV) technique. The leading-edge radius is shown to affect the size and location of the vortices and also the vortex bursting location over the models. As a result of this, the leadingedge radius also affects the forces and moment acting on a 50 o delta wing.

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