Topic
Lift-induced drag
About: Lift-induced drag is a research topic. Over the lifetime, 2861 publications have been published within this topic receiving 41094 citations.
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23 Jun 1997
TL;DR: In this paper, a universal wake survey data analysis code which is compatible with different types of wake data acquisition systems has been developed, which is based on the theories of Maskell and Betz and rewrite the drag and lift integrals in terms of flow variables measured inside the wake region.
Abstract: A universal wake survey data analysis code which is compatible with different types of wake data acquisition systems has been developed. The theories of Maskell and Betz are used. Their basic approach is to rewrite the drag and lift integrals in terms of flow variables measured inside the wake region. Quantitative wake surveys allow separate measurements of profile drag, induced drag, and lift, including sectional distributions of lift and drag. Some wake survey data analysis results are also discussed in order to demonstrate the general capabilities of the currently developed code.
34 citations
TL;DR: In this article, an active flow control (AFC) system was applied to a nominally 2D circular cylinder, an archetype bluff-body configurations, with the purpose of drag reduction and wake stabilization.
34 citations
TL;DR: In this paper, a numerical analysis is performed to investigate the aerodynamic characteristics and the static height stability of the endplate and the anhedral angle on an aspect-ratio-one wing-in-ground effect.
Abstract: A numerical analysis is performed to investigate the aerodynamic characteristics and the static height stability of the endplate and the anhedral angle on an aspect-ratio-one wing-in-ground effect. The analysis shows that the ground effect increases the lift by the high pressure on the lower surface, reduces the drag, increases the suction on the upper surface, and considerably enhances the lift-drag ratio. The endplate, which prevents the high-pressure air from escaping out of the lower surface and reduces the influence of the wing-tip vortex, further augments the lift and the lift-drag ratio. Irodov's criteria are also numerically evaluated in order to investigate the static height stability. The comparison of Irodov's criteria shows that the endplate is not favorable for the static height stability. However, the anhedral angle improves the lift as well as Irodov's criteria at various angles of attack and heights. Interestingly, the stagnation point for the anhedral angle moves forward with decreasing height at the low angles of attack and leads an increase in the pressure drag at the leading edge. This increase nullifies the advantages of the induced drag and the pressure drag. Thus, the lift-drag ratio of a wing is not improved as much with an anhedral angle as it is with an endplate.
34 citations
TL;DR: In this article, general integral expressions are derived for the nonlinear lift and pitching moment of arbitrary wing planforms in subsonic flow using the suction analogy and an assumed pressure distribution based on classical linear theory results.
Abstract: General integral expressions are derived for the nonlinear lift and pitching moment of arbitrary wing planforms in subsonic flow The analysis uses the suction analogy and an assumed pressure distribution based on classical linear theory results The potential flow lift constant and certain wing geometric parameters are the only unknowns in the integral expressions Results of the analysis are compared with experimental data and other numerical methods for several representative wings, including ogee and double-delta planforms The present method is shown to be as accurate as other numerical schemes for predicting total lift, induced drag, and pitching moment b c c CL CD Cm CT Cs cc, ccd E2 Nomenclature = aspect ratio = wing span =chord = reference length = lift coefficient = drag coefficient = pitching moment coefficient = thrust coefficient = suction coefficient = section lift coefficient = section induced drag coefficient = section suction coefficient = pressure loading coefficient = drag = proportionality constant, Eq (32) = proportionality constant, Eq (53) = chordwise function, Eq (44) ff(rj) = span wise f unction, Eq (28) K = potential constant L =lift loading constant, Eq (5) S = suction force SR = reference area s = suction force per unit length T = leading edge thrust, Eq (7) T' = leading edge thrust per unit length V = freestream speed Wj = downwash velocity component, Eq (11) a = angle of attack F = vorticity p = freestream density £ = nondimensional chordwise coordinate 77 = nondimensional spanwise coordinate A = leading edge sweep angle Subscripts P = potential flow E =edge / = induced VLE = leading edge vortex VSE = side edge vortex
34 citations
TL;DR: In this paper, the aerodynamics of a sailing yacht with different sail trims are presented, derived from simulations performed using computational fluid dynamics, and a verification and validation of the computed aerodynamic forces and pressure distributions are performed.
34 citations