Minimizing Induced Drag with Wing Twist, Computational-Fluid-Dynamics Validation

Phillips, Warren F.; Fugal, Spencer R.; Spall, Robert E.

doi:10.2514/1.15089

Cited by 65 publications

(65 citation statements)

References 6 publications

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“…In the present work, closed-form relations for estimating induced-drag and lift coefficients for untwisted wings in ground effect are developed by correlating results obtained from numerical solutions [9] to Prandtl's lifting-line theory [32,33], which produces results in good agreement with inviscid CFD solutions [34] at a small fraction of the computational cost.…”

Section: Ratio Of Wing Height To Wingspanmentioning

confidence: 91%

Lifting-Line Predictions for Induced Drag and Lift in Ground Effect

Phillips

Hunsaker

2013

31st AIAA Applied Aerodynamics Conference

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Closed-form relations are presented for estimating ratios of the induced-drag and lift coefficients acting on a wing in ground effect to those acting on the same wing outside the influence of ground effect. The closed-form relations for these ground-effect influence ratios were developed by correlating results obtained from numerical solutions to Prandtl's liftingline theory. Results show that these influence ratios are not unique functions of the ratio of wing height to wingspan, as is sometimes suggested in the literature. These ground-effect influence ratios also depend on the wing planform, aspect ratio, and lift coefficient. = tapered-wing correction coefficients, Eqs. (13) and (15)

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Section: Ratio Of Wing Height To Wingspanmentioning

confidence: 91%

Lifting-Line Predictions for Induced Drag and Lift in Ground Effect

Phillips

Hunsaker

2013

31st AIAA Applied Aerodynamics Conference

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“…8 Stall control can be achieved using a linear twist distribution, v u ð Þ linear , along b, which is uncomplicated to implement if the twist is simply geometric. However, previous research [9][10][11][12] suggests that linear twist is not the optimum twist distribution for a wing with linear taper. Greater aerodynamic efficiency can be attained by using optimum total twist, O opt , combined with an optimum elliptical spanwise twist distribution, v u ð Þ opt , that generate uniform upwash along b, an elliptical downforce distribution and minimum induced drag for the wing with linear taper, to yield nearly the same aerodynamic performance as a straight wing of elliptic planform.…”

Section: Introductionmentioning

confidence: 93%

“…This is expected, as theory determines that a twisted wing will generate induced drag even when set at a L0 . 10,11,20 Geometric twist facilitates a partial wing stall since the mid-span region, which is set at higher a, will stall first. 3,19 Partial wing stall is an important design parameter in aviation that may also contribute to safety in motor racing.…”

Section: Upwash Distributionmentioning

confidence: 99%

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Design of the Grand Touring sports car wing: geometric and aerodynamic twist

Marques-Bruna

2012

Proceedings of the Institution of Mechanical Engineers, Part P:

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Wing twist gives the Grand Touring sports car an eye-catching 'aerodynamic shape'. From the functional viewpoint, wing twist may improve downforce, provide stall control and enhance aerodynamic efficiency if the twist is optimised. This study aims, first, to explore the influence of linear geometric and aerodynamic twist upon spanwise upwash velocity, downforce and induced drag distributions and, second, to evaluate the use of optimum twist in achieving minimum induced drag while preserving high downforce, in wings with linear taper for the Grand Touring car. Baseline wing prototypes were designed and fitted, subsequently, with a Gurney flap and endplates to obtain complete wings. Aerodynamics for straight wings and wings with geometric, aerodynamic and optimised twist were computed using modified versions of the Prandtl's Lifting-line Theory. Straight and geometrically-twisted wings with constituent NACA 65 1 -412 airfoils present superior aerodynamic efficiency at angles of attack 4 1°and may be used as stabilisers on high-speed circuits. Geometric twisting elicits a partial, rather than complete, wing stall that contributes to safety in motor racing. A geometrically-twisted wing constructed with a NASA LS(1)-0413 airfoil yields high downforce at the expense of large induced drag via a double-peaked induced drag distribution, and it is suitable for high-downforce racing circuits. Nonetheless, the analysis suggests that a twist-optimised wing for the Grand Touring car very nearly duplicates the ideal aerodynamic performance of an elliptic wing and yields high downforce and minimum possible induced drag. The findings support the implementation of optimum wing twist at the conceptual stages of Grand Touring sports car design.

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“…(6) can be used to obtain an analytical solution for the location of the semispan aerodynamic center of an unswept wing. Using an alternate form of the lifting-line solution for twisted wings [16][17][18][19], it has been shown that Eq. (6) can be written as [20] …”

Section: Analytical Solution For Unswept Wingsmentioning

confidence: 99%

Estimating the Subsonic Aerodynamic Center and Moment Components for Swept Wings

Phillips

Hunsaker

Niewoehner

2008

46th AIAA Aerospace Sciences Meeting and Exhibit

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An improved method is presented for estimating the subsonic location of the semispan aerodynamic center of a swept wing and the aerodynamic moment components about that aerodynamic center. The method applies to wings with constant linear taper and constant quarter-chord sweep. The results of a computational fluid dynamics study for 236 wings show that the position of the semispan aerodynamic center of a wing depends primarily on aspect ratio, taper ratio, and quarter-chord sweep angle. Wing aspect ratio was varied from 4.0 to 20, taper ratios from 0.25 to 1.0 were investigated, quarter-chord sweep angles were varied from 0 to 50 degrees, and linear geometric washout was varied from − 4.0 to +8.0 degrees. All wings had airfoil sections from the NACA 4-digit airfoil series with camber varied from 0 to 4 percent and thickness ranging from 6 to 18 percent. Within the range of parameters studied, wing camber, thickness, and twist were shown to have no significant effect on the position of the semispan aerodynamic center. The results of this study provide improved resolution of the semispan aerodynamic center and moment components for conceptual design and analysis. b n = twist contribution to the Fourier coefficients in the series solution to the lifting-line equation

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Minimizing Induced Drag with Wing Twist, Computational-Fluid-Dynamics Validation

Cited by 65 publications

References 6 publications

Lifting-Line Predictions for Induced Drag and Lift in Ground Effect

Lifting-Line Predictions for Induced Drag and Lift in Ground Effect

Design of the Grand Touring sports car wing: geometric and aerodynamic twist

Estimating the Subsonic Aerodynamic Center and Moment Components for Swept Wings

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