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.

Effects of upper surface modification on the aerodynamic characteristics of the NACA 63 sub 2-215 airfoil section

Abstract: An upper surface modification designed to increase the maximum lift coefficient of a 63 sub 2 - 215 airfoil section was tested at Mach numbers of 0.2, 0.3, and 0.4 Reynolds numbers of 1.3 x 1 million, 2 x 10 sub 6 and 2.5 x 1 million. Comparisons of the aerodynamic coefficients before and after the modification were made. The upper surface modification increased the maximum lift coefficient of the airfoil significantly at all conditions.

A semianalytical expression for the drag force of an interactive particle due to wake effect

Abstract: The drag forces of particles aligned in a line parallel to the direction of relative motion between the fluid stream and the particles are investigated. The particle−particle interactions and the wake effect should be taken into account for quantitatively describing the drag force of the interactive particle. Under the circumstances of the Reynolds number (Re) being around 100, the drag force of the interactive trailing particle is analyzed based on the velocity distribution in the far wake region downstream of the leading particle. As a result, a semianalytical expression for the drag force of the trailing particle is formulated. It is utilized to calculate the drag force ratio of the trailing particle for Re of 54−154. Agreement between the calculation and the measured data is achieved.

Dynamics of viscoelastic fluid in a rotating soft microchannel

Abstract: In this study, we numerically investigate the effects of rotational forces, viz., centrifugal force and Coriolis force, on the flow dynamics of a viscoelastic fluid in a polymeric layer grafted microchannel. The viscoelastic fluid is represented by the Oldroyd-B model, and the effect of viscoelasticity on the underlying transport is studied. A numerical procedure consistent with the finite difference method is used to solve the system of partial differential equations. The numerical model takes into consideration, among many others, the drag effects of the “soft layer” and the transiences in the flow dynamics leading to the steady state. The complex interplay between the effect of rotational forcing and the presence of the soft layer is observed to lead to vital conclusions that could improve the design of many lab-on-a-compact disc based microfluidic devices. In addition, the effect of elasticity on the flow dynamics in the presence of rotational forces and soft layer induced drag force is studied. The in-house numerical code employs the finite difference numerical scheme to discretize the equations and consequently solves the obtained system of linear algebraic equations using the Gauss–Seidel iterative scheme. By demonstrating the velocity profiles, we discuss the effect of the various rheological parameters on the underlying transport feature. Finally, the effect of the rotation on the net throughput is studied extensively.

Induced drag ideal efficiency factor of arbitrary lateral-vertical wing forms

Abstract: A relatively simple equation is presented for estimating the induced drag ideal efficiency factor e for arbitrary cross sectional wing forms. This equation is based on eight basic but varied wing configurations which have exact solutions. The e function which relates the basic wings is developed statistically and is a continuous function of configuration geometry. The basic wing configurations include boxwings shaped as a rectangle, ellipse, and diamond; the V-wing; end-plate wing; 90 degree cruciform; circle dumbbell; and biplane. Example applications of the e equations are made to many wing forms such as wings with struts which form partial span rectangle dumbbell wings; bowtie, cruciform, winglet, and fan wings; and multiwings. Derivations are presented in the appendices of exact closed form solutions found of e for the V-wing and 90 degree cruciform wing and for an asymptotic solution for multiwings.

Integrated Design of a Morphing Winglet for Active Load Control and Alleviation of Turboprop Regional Aircraft

Abstract: Aircraft winglets are well-established devices that improve aircraft fuel efficiency by enabling a higher lift over drag ratios and lower induced drag. Retrofitting winglets to existing aircraft also increases aircraft payload/range by the same order of the fuel burn savings, although the additional loads and moments imparted to the wing may impact structural interfaces, adding more weight to the wing. Winglet installation on aircraft wing influences numerous design parameters and requires a proper balance between aerodynamics and weight efficiency. Advanced dynamic aeroelastic analyses of the wing/winglet structure are also crucial for this assessment. Within the scope of the Clean Sky 2 REG IADP Airgreen 2 project, targeting novel technologies for next-generation regional aircraft, this paper deals with the integrated design of a full-scale morphing winglet for the purpose of improving aircraft aerodynamic efficiency in off-design flight conditions, lowering wing-bending moments due to maneuvers and increasing aircraft flight stability through morphing technology. A fault-tolerant morphing winglet architecture, based on two independent and asynchronous control surfaces with variable camber and differential settings, is presented. The system is designed to face different flight situations by a proper action on the movable control tabs. The potential for reducing wing and winglet loads by means of the winglet control surfaces is numerically assessed, along with the expected aerodynamic performance and the actuation systems’ integration in the winglet surface geometry. Such a device was designed by CIRA for regional aircraft installation, whereas the aerodynamic benefits and performance were estimated by ONERA on the natural laminar flow wing. An active load controller was developed by PoliMI and UniNA performed aeroelastic trade-offs and flutter calculations due to the coupling of winglet movable harmonics and aircraft wing bending and torsion.