A Survey of Factors Affecting Blunt-Leading-Edge Separation for Swept and Semi-Slender Wings

Luckring, James M.

doi:10.2514/6.2010-4820

Cited by 35 publications

(17 citation statements)

References 31 publications

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“…Before reaching stall, the C L -gradient decreases. This lift slope is typical for blunt non-slender wing configurations: the vortical lift portion is barely measurable, concluding the formation of a rather weak vortex [22]. The maximum lift is reached at…”

Section: Leading-edge Roughness Effectmentioning

confidence: 87%

Leading-Edge Roughness Affecting Diamond-Wing Aerodynamic Characteristics

et al. 2018

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Diamond wing configurations for low signature vehicles have been studied in recent years. Yet, despite numerous research on highly swept, sharp edged wings, little research on aerodynamics of semi-slender wings with blunt leading-edges exists. This paper reports on the stall characteristics of the AVT-183 diamond wing configuration with variation of leading-edge roughness size and Reynolds number. Wind tunnel testing applying force and surface pressure measurements are conducted and the results presented and analysed. For the investigated Reynolds number range of 2.1 × 10 6 ≤ R e ≤ 2.7 × 10 6 there is no significant influence on the aerodynamic coefficients. However, leading-edge roughness height influences the vortex separation location. Trip dots produced the most downstream located vortex separation onset. Increasing the roughness size shifts the separation onset upstream. Prior to stall, global aerodynamic coefficients are little influenced by leading-edge roughness. In contrast, maximum lift and maximum angle of attack is reduced with increasing disturbance height. Surface pressure fluctuations show dominant broadband frequency peaks, distinctive for moderate sweep vortex breakdown. The experimental work presented here provides insights into the aerodynamic characteristics of diamond wings in a wide parameter space including a relevant angle of attack range up to post-stall.

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Section: Leading-edge Roughness Effectmentioning

confidence: 87%

Leading-Edge Roughness Affecting Diamond-Wing Aerodynamic Characteristics

et al. 2018

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“…On delta wings with rounded leading edges, the flow separation point is not fixed at the leading edge and depends on the Reynolds number and the leading edge curvature. The origin of the leading edge vortex is at the delta wing apex for a sharp-edged wing but it is further downstream for a rounded tip [29]. The leading-edge vortices from sharp edges are steady for a wide range of angles of attack.…”

Section: Vortical Flowsmentioning

confidence: 95%

“…Only if the angle of attack increases greatly, these vortices become unsteady and separate starting from the trailing edge of the wing. The flow at blunt nose, however, separates at moderate to high angles of attack starting from an outboard and aft location near the trailing edge [29]…”

Section: Vortical Flowsmentioning

confidence: 99%

Vortical flow prediction of a diamond wing with rounded leading edges

Ghoreyshi

Ryszka

Cummings

et al. 2016

Aerospace Science and Technology

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“…The origin of the leading edge vortex is at the delta wing apex for a sharp-edged wing but it is further downstream for a rounded tip. 29 The leading-edge vortices from sharp edges are steady for a wide range of angles of attack. Only if the angle of attack increases greatly, these vortices become unsteady and separate starting from the trailing edge of the wing.…”

Section: Vortical Flowsmentioning

confidence: 99%

Vortical Flow Prediction of the AVT-183 Diamond Wing

Ghoreyshi

Ryszka

Cummings

et al. 2015

53rd AIAA Aerospace Sciences Meeting

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The objective of this paper is to assess the potential and limitations of current practice in computational fluid dynamic modeling for predicting vortical flowfields over a generic 53-degree swept diamond wing with rounded leading edges. This wing was designed under STO AVT Task Group 183 and is based on the SACCON UCAV geometry, which is a lambda wing with complex span-wise distributions of thickness and leading edge radius and with a linear twist outboard of the first trailing edge break. The SACCON wing trailing-edge was swept forward by 26.5-degrees to form a diamond-shaped planform that is used in this study. This new wing also has a constant NACA 64A-006 airfoil section with a leading edge radius of 0.264 percent chord and has no twist. CFD simulations were performed for various angles of attack at a Mach number of 0.15 and a Reynolds number of 2.7× 10 6 based on the mean aerodynamic chord to match experiments. CFD simulations were run with different turbulence models and with a limited assessment of Delayed Detached Eddy Simulation. The wind tunnel experiments of the diamond wing were carried out in the and include aerodynamic lift, drag, and pitch moment measurements as well as span-wise pressure distributions at different chord-wise locations. This data set is used to validate the CFD results. The results presented demonstrate that the CFD compare well with the experiments at small angles of attack; the pitch moment predicted by the SARC turbulence model provide a better match to experimental results than the SA model at moderate angles of attack; and at high angles of attack, CFD predictions are not as good. The flow visualization results show that a leading-edge vortex is formed above the upper surface of the wing at an angle of attack of about eight degrees. This vortex becomes larger and stronger when the angle of attack is increased. With increasing angle of attack, the vortex formation point moves upstream and the vortex core moves inboard towards the wing center. Finally, the results show that the flow over the diamond wing is steady throughout the range of angles of attack.

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A Survey of Factors Affecting Blunt-Leading-Edge Separation for Swept and Semi-Slender Wings

Cited by 35 publications

References 31 publications

Leading-Edge Roughness Affecting Diamond-Wing Aerodynamic Characteristics

Leading-Edge Roughness Affecting Diamond-Wing Aerodynamic Characteristics

Vortical flow prediction of a diamond wing with rounded leading edges

Vortical Flow Prediction of the AVT-183 Diamond Wing

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