A study of the vortex flow over a 76/40-deg double-delta wing

Verhaagen, N.G.; Jenkins, Luther N.; Kern, S; Washburn, Anthony E.

doi:10.2514/6.1995-650

Cited by 47 publications

(26 citation statements)

References 8 publications

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“…In this paper, only test data that help illustrate the effects of the Reynolds number are shown. More test details and results can be found in the original data reports by Verhaagen, et al [4]. Fig.…”

Section: Off-surface Flowmentioning

confidence: 92%

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Effects of Reynolds number on the flow over 76/40-deg double-delta wings

Verhaagen

1999

17th Applied Aerodynamics Conference

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The effects of the Reynolds number on the flow over 76/40-deg double-delta or strake-wing configurations are described using existing and hitherto unpublished experimental data. In addition, the capability of numerical solutions to predict these effects is discussed. The flow over the strake appears to be little affected by the Reynolds number.On the wing, strong Reynolds-number effects are evident. on the flow on and off the wing surface. Numerical solutions tend to reasonably well predict the flow over this type of configurations. b C CP M Re Re, s X,Y,Z a, A0.4 (ye Nomenclature wing span root chord length static-pressure coefficient freestream Mach number Reynolds number, per meter chord Reynolds number, based on root chord local wing semispan coordinates of wing-axes system, origin at apex geometric angle of attack effective angle of attack Introduct ionDouble-delta or strake-wing configurations are employed for several modern fighter aircraft to obtain a high maneuverability. The highly swept strake is an additional lifting surface above which a stable vortex is formed. This vortex stabilizes the flow over m Research the wing and enhances the lift-to-drag efficiency of the aircraft. The shedding, interaction and breakdown of the vortices formed over the strake and wing depend on the aircraft geometry and flight conditions. Apart from the beneficial effect of enhancing the aircraft lift and maneuverability, these vortices may also contribute in serious structural fatigue problems, such as the tail-buffet problem of fighter aircraft.The basic planform representative of highlymaneuverable strake-wing aircraft is characterized by a strake and wing leading-edge sweep angle of 76 and 40 deg, respectively, and a strake-wing leadingedge junction at approximately mid chord [l]. Numerical solutions of the flow over this type of planform were obtained by, among others, Kern [l]: Hsu and Liu [2] and Ekaterinaris, et al [3]. Some of their predictions are given here in Fig. 1. The solutions show shedding of the vortices from the strake and wing leading edges, and a strong interaction and breakdown of these vortices over the wing. To validate the numerical predictions obtained by Kern [l], extensive experimental studies were conducted on a 76/40-deg double-delta-wing model constructed by N.4WC (Naval Air Warfare Center). This model was tested at different test conditions in wind tunnels at N.4WC and NASA LaRC (Langley Research Center). Up to now only results of the testings conducted in the BART (Basic -4erodynamics Research 'Jrunnel) at N.4S.4 LaRC have been published [4].The tests show that the flow over the double-delta wing is sensible to Reynolds number effects. Evidence of these effects is also obtained from experimental studies conducted by Fritzelas, et al [5]: Carson and Verhaagen [6], and Rogers and Verhaagen [7] on similarly shaped double-delta-wing models. An overview of the effects of the Reynolds number on the flow over straight leading-edge delta wings is given by Visser and Washburn [B]. While the majority ...

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Section: Off-surface Flowmentioning

confidence: 92%

“…This model was tested at different test conditions in wind tunnels at N.4WC and NASA LaRC (Langley Research Center). Up to now only results of the testings conducted in the BART (Basic -4erodynamics Research 'Jrunnel) at N.4S.4 LaRC have been published [4].…”

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confidence: 99%

Effects of Reynolds number on the flow over 76/40-deg double-delta wings

Verhaagen

1999

17th Applied Aerodynamics Conference

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“…The wing vortices are stronger than the strake vortices, hence they breakdown first. The breakdown of the strake vortices is then triggered by the breakdown of the wing vortices (Verhaagen, 1995). Although the breakdown of the strake vortices over the wing can be observed at large incidences as shown in Fig.…”

Section: Article In Pressmentioning

confidence: 96%

Characteristics of fin buffeting over delta wings

Lambert

Gursul

2004

Journal of Fluids and Structures

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“…His overview also includes oil-film visualization for determination of the corresponding patterns of surface shear stress lines as a function of Reynolds number. Further investigations on the effects of Reynolds number have focused on relatively high values extending from 0.5 to 2.5 × 10 6 , as described by Visser and Washburn 3 and Verhaagen et al 4 These investigations also included variations of angle of attack. Visser and Washburn 3 focused on the boundary-layer transition on delta wings having a flat surface on the leeward side.…”

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confidence: 98%

“…Furthermore, it was found that the occurrence of transition was strongly correlated with the strength of the vortex, as represented by its circulation evaluated in the crossflow plane. Verhaagen et al 4 characterized the effect of Reynolds number on the surface pressure coefficient along the leeward surface of the wing and, furthermore, showed the effect of Reynolds number on qualitative visualization, as well as on topological representations of the surface flow patterns.…”

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confidence: 99%