scispace - formally typeset
Search or ask a question
Topic

Airfoil

About: Airfoil is a research topic. Over the lifetime, 24696 publications have been published within this topic receiving 337709 citations. The topic is also known as: aerofoil & wing section.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, a new approach to extract useful design information from Pareto-optimal solutions of optimization problems is proposed and applied to an aerodynamic transonic airfoil shape optimization.
Abstract: A new approach to extract useful design information from Pareto-optimal solutions of optimization problems is proposed and applied to an aerodynamic transonic airfoil shape optimization. The proposed approach enables an analysis of line, face, or volume data of all Pareto-optimal solutions such as shape and flow field by decomposing the data into principal modes and corresponding base vectors using proper orthogonal decomposition (POD). Analysis of the shape and surface pressure data of the Pareto-optimal solutions of an aerodynamic transonic airfoil shape optimization problem showed that the optimized airfoils can be categorized into two families (low drag designs and high lift designs), where the lift is increased by changing the camber near the trailing edge among the low drag designs while the lift is increased by moving the lower surface upward among the high lift designs.

81 citations

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional local inviscid-viscous interaction technique for the analysis of airfoil transitional separation bubbles, ALESEP (Airfoil Leading Edge Separation), has been extended for the calculation of transition separation bubbles over infinite swept wings.
Abstract: A previously developed two-dimensional local inviscid-viscous interaction technique for the analysis of airfoil transitional separation bubbles, ALESEP (Airfoil Leading Edge Separation), has been extended for the calculation of transitional separation bubbles over infinite swept wings. As part of this effort, Roberts' empirical correlation, which is interpreted as a separated flow empirical extension of Mack's stability theory for attached flows, has been incorporated into the ALESEP procedure for the prediction of the transition location within the separation bubble. In addition, the viscous procedure used in the ALESEP techniques has been modified to allow for wall suction. A series of two-dimensional calculations is presented as a verification of the prediction capability of the interaction techniques with the Roberts' transition model. Numerical tests have shown that this two-dimensional natural transition correlation may also be applied to transitional separation bubbles over infinite swept wings. Results of the interaction procedure are compared with Horton's detailed experimental data for separated flow over a swept plate which demonstrates the accuracy of the present technique. Wall suction has been applied to a similar interaction calculation to demonstrate its effect on the separation bubble. The principal conclusion of this paper is that the prediction of transitional separation bubbles over two-dimensional or infinite swept geometries is now possible using the present interacting boundary layer approach.

81 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental investigation of the near wake of a thin airfoil at various incidence angles was performed in a wind tunnel, and the wake structure was measured using hot-wire sensors.
Abstract: An experimental investigation of the near wake of a thin airfoil at various incidence angles is reported in this paper. The airfoil (NACA 0012 basic thickness form) was located in a wind tunnel, and the wake structure was measured using hot-wire sensors. The measurements of mean-velocity, turbulence intensity and Reynolds-stress components across the wake at several distances downstream show the complex nature of the near wake and its asymmetrical behavior. The asymmetry in the wake property, which is maintained up to a length of 1.5 chords downstream of the trailing edge of the blade, is dependent on the incidence angle of the inlet flow. The streamwise velocity defect in an asymmetric wake decays more slowly compared to that of a symmetric wake. The streamline curvature due to the blade loading has a substantial effect on the mean velocity profile as well as the turbulence structure. The numerical study of the same wake indicates that the existing turbulence closure models need some modification to account for the asymmetric characteristics of the wake.

81 citations

Journal ArticleDOI
TL;DR: In this article, a thin-airfoil theory is applied to the lift problem of an airfoil with a Gurney flap, and the lift and pitching moment coefficient increments are given as a square-root function of the relative Gurny flap height, and they are proportionally related.
Abstract: Thin-airfoil theory is applied to the lift problem of an airfoil with a Gurney flap. The lift and pitching moment coefficient increments are given as a square-root function of the relative Gurney flap height, and they are proportionally related. This model interprets the Gurney flap lift enhancement as a special camber effect. The theoretical relations are in good agreement with experimental and numerical data for several different wings. The theoretical method developed in this paper can be applied to similar trailing-edge devices for lift enhancement, and it is useful in the preliminary design of these flow control devices.

81 citations

Patent
14 Jul 1992
TL;DR: An unmanned aerial vehicle (10) having a toroidal fuselage (20) that surrounds a pair of coaxial, multibladed, counter-ro-tating rotors (40) has an airfoil profile optimized to provide high hover efficiency and produce a pressure distribution that provide high lift forces.
Abstract: An unmanned aerial vehicle (10) having a toroidal fuselage (20) that surrounds a pair of coaxial, multibladed, counter-ro-tating rotors (40). The toroidal fuselage (20) has an airfoil profile that is optimized to provide high hover efficiency and produce a pressure distribution that provide high lift forces. The airfoil profile is further optimized to counteract the undesirable nose-up pitching moments experienced by ducted rotary-type UAVs in forward translational flight.

81 citations


Network Information
Related Topics (5)
Reynolds number
68.4K papers, 1.6M citations
80% related
Boundary layer
64.9K papers, 1.4M citations
77% related
Laminar flow
56K papers, 1.2M citations
76% related
Rotor (electric)
179.9K papers, 1.2M citations
75% related
Vortex
72.3K papers, 1.3M citations
75% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,083
20221,871
2021923
2020979
20191,097
20181,002