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.

Flow over an aerofoil without and with a leading-edge slat at a transitional Reynolds number:

Abstract: In this study, a multi-element aerofoil including NACA2415 aerofoil with NACA22 leading-edge slat is experimentally and computationally investigated at a transitional Reynolds number of 2×105. In the experiment, the single-element aerofoil experiences a laminar separation bubble, and a maximum lift coefficient of 1.3 at a stall angle of attack of 12° is obtained. This flow has been numerically simulated by FLUENT, employing the recently developed, k—kL—ω and k—ω shear—stress transport (SST) transition models. Both transition models are shown to accurately predict the location of the experimentally determined separation bubble. Experimental measurements also illustrate that the leading-edge slat significantly delays the stall up to an angle of attack of 20°, with a maximum lift coefficient of 1.9. The fluid dynamics governing this improvement is the elimination of the separation bubble by the injection of high momentum fluid through the slat over the main aerofoil — an efficient means of flow contr...

Concise Orthogonal Representation of Supercritical Airfoils

Abstract: The combination of optimization algorithms and computational fluid dynamics offers promise for the development of improved aerodynamic designs. Optimization strategies have a common reuirement for representation of geometry by a number of design parameters. For wing design the parameterization is generally separable into a representation of the planform and the representation of airfoil sections at a number of spanwise positions. The representation of airfoil sections is considered here with particular emphasis on the requirements of conceptual wing design.

The design and testing of a winglet airfoil for low-speed aircraft

Abstract: The PSU 94-097 airfoil has been designed for use on winglets of high-performance sailplanes. The design problem is difficult because the airfoil must operate over a wide range of Reynolds numbers, and this range includes values that are relatively low. To validate the design tools, as well as the design itself, the airfoil was tested in the Penn State Low-Speed, Low-Turbulence Wind Tunnel from Reynolds numbers of 2.4 × 10 5 to 1.0 × 10 6 . In addition to transition-free measurements, potential drag reductions using artificial turbulators were explored, although the benefits were found to be limited for this application. Finally, performance predictions from two well-known computer codes are compared to the data obtained experimentally, and both are found to generate results that are in good agreement with the wind-tunnel measurements. Nomenclature CP pressure coefficient, (pl - p∞ )/q∞ L. lower surface R Reynolds number based on free-stream conditions and airfoil chord S. boundary-layer separation location, xS/c T. boundary-layer transition location, xT/c U. upper surface c airfoil chord cd profile-drag coefficient cl section lift coefficient cm section pitching-moment coefficient about the quarter-chord point p static pressure, Pa (lbf/ft 2

Induced-Drag Calculations in the Unsteady Vortex Lattice Method

Abstract: α angle of attack, rad Γ circulation, m2s−1 λ wake wavelength, m ρ∞ free-stream air density, kgm −3 τ panel tangential vector ω angular velocity, rad s−1 a non-dimensional distance between aerofoil mid-chord and centre of rotation A panel area, m b semi-chord, m ∆b panel span, m B wingspan, m c aerofoil chord, m ∆c panel chord, m C Theodorsen’s function, C(k) = F (k) + iG(k) Cd sectional drag coefficient CD wing drag coefficient Cl sectional lift coefficient Cs sectional leading-edge suction coefficient ∗Graduate Student, Department of Aeronautics. AIAA Student Member. †Senior Lecturer, Department of Aeronautics. E-mail: rpalacio@imperial.ac.uk. AIAA Member. ‡Lecturer, Department of Mechanical Engineering Sciences. AIAA Member.

Modeling and Experiment of Leading Edge Separation Control Using SDBD Plasma Actuators

Abstract: This work presents the study of the single-dielectric barrier discharge aerodynamic plasma actuator. To model the physics of the plasma discharge, a space-time lumpedelement circuit model was developed. The model solution compared well to some of the characteristic features of the discharge such as the dependence of the sweep velocity and maximum extent of the ionized air as functions of the applied voltage and a.c. driving frequency. The time-dependent charge distribution obtained from the model was used to provide boundary conditions to the electric field equation that was used to calculate the time dependent electric potential. The was then used to calculate the space-time distribution of the actuator body force. An application of the plasma actuators to the leading-edge separation control on the NACA 0021 airfoil was studied numerically and experimentally. The results were obtained for a range of angles of attack for uncontrolled flow, and steady and unsteady plasma actuators located at the leading edge of the airfoil. The control of the lift stall was of particular interest. Improvement in the airfoil characteristics were observed in the numerical simulations at post-stall angles of attack with the plasma actuators. The computational results corresponded very well with the experiments.