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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.


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Journal ArticleDOI
TL;DR: In this paper, a genetic algorithm was applied to optimize target pressure distributions for inverse design methods, where pressure distributions around airfoils were parameterized by B-spline polygons, and the airfoil drag was minimized under constraints on lift, air foil thickness, and other design principles.
Abstract: A genetic algorithm has been applied to optimize target pressure distributions for inverse design methods. Pressure distributions around airfoils are parameterized by B-spline polygons, and the airfoil drag is minimized under constraints on lift, airfoil thickness, and other design principles. Once target pressure distributions are obtained, corresponding airfoil/wing geometries can be computed by an inverse design code coupled with a Navier-Stokes solver. Successful design results were obtained for transonic cases with and without a shock wave.

132 citations

Journal ArticleDOI
TL;DR: In this paper, a rod-airfoil air flow by time-resolved Tomographic Particle Image Velocimetry (TR-TOMO PIV) in thin-light volume configuration was investigated at the region close to the leading edge of a NACA0012 airfoil embedded in the von Karman wake of a cylindrical rod.
Abstract: This work investigates the rod-airfoil air flow by time-resolved Tomographic Particle Image Velocimetry (TR-TOMO PIV) in thin-light volume configuration. Experiments are performed at the region close to the leading edge of a NACA0012 airfoil embedded in the von Karman wake of a cylindrical rod. The 3D velocity field measured at 5 kHz is used to evaluate the instantaneous planar pressure field by integration of the pressure gradient field. The experimental data are treated with a discretized model based on multiple velocity measurements. The time separation used to evaluate the Lagrangian derivative along a fluid parcel trajectory has to be taken into account to reduce precision error. By comparing Lagrangian and Eulerian approaches, the latter is restricted to shorter time separations and is found not applicable to evaluate pressure gradient field if a relative precision error lower than 10% is required. Finally, the pressure evaluated from tomographic velocity measurements is compared to that obtained from simulated planar ones to discuss the effect of 3D flow phenomena on the accuracy of the proposed technique.

132 citations

Journal ArticleDOI
TL;DR: In this article, the thrust and/or propulsive efficiency of a single flapping airfoil is maximized by using a numerical optimization method based on the steepest ascent.
Abstract: The thrust and/or propulsive efficiency of a single flapping airfoil is maximized by using a numerical optimization method based on the steepest ascent. The flapping motion of the airfoil is described by a combined sinusoidal plunge and pitching motion. Optimization parameters are taken to be the amplitudes of the plunge and pitching motions and the phase shift between them at a fixed flapping frequency. Two-dimensional, unsteady, low-speed, laminar, and turbulent flows are computed by using a Navier‐Stokes solver on moving overset grids. Computations are performed in parallel in a computer cluster. The optimization data show that high thrust values may be obtained at the expense of propulsive efficiency. For a high propulsive efficiency, the effective angle of attack of the airfoil is reduced, and large-scale vortex formations at the leading edge are prevented.

132 citations

01 Jun 1985
TL;DR: In this paper, the supercritical flows at high subsonic speeds over a NACA 0012 airfoil were studied to acquire aerodynamic data suitable for evaluating numerical flow codes.
Abstract: The supercritical flows at high subsonic speeds over a NACA 0012 airfoil were studied to acquire aerodynamic data suitable for evaluating numerical-flow codes. The measurements consisted primarily of static and dynamic pressures on the airfoil and test-channel walls. Shadowgraphs were also taken of the flow field near the airfoil. The tests were performed at free-stream Mach numbers from approximately 0.7 to 0.8, at angles of attack sufficient to include the onset of buffet, and at Reynolds numbers from 1 million to 14 million. A test action was designed specifically to obtain two-dimensional airfoil data with a minimum of wall interference effects. Boundary-layer suction panels were used to minimize sidewall interference effects. Flexible upper and lower walls allow test-channel area-ruling to nullify Mach number changes induced by the mass removal, to correct for longitudinal boundary-layer growth, and to provide contouring compatible with the streamlines of the model in free air.

132 citations

Book
01 Jan 1986
TL;DR: In this article, a simulation method for strongly interacting Viscous Transonic Flow is presented, which is used for coupling and separation procedures for attached and separated flows on Swept and Tapered Wings.
Abstract: Stewartson Memorial Lecture: Experiments are Telling You Something.- 1. Two- and Three-Dimensional Steady Flows.- 1. Predictions of Airfoil Aerodynamic Performance Degradation Due to Icing.- 2. VISTRAFS: A Simulation Method for Strongly Interacting Viscous Transonic Flow.- 3. Coupling Procedures for Viscous-Inviscid Interaction for Attached and Separated Flows on Swept and Tapered Wings.- 4. New Possibilities of Viscous-Inviscid Numerical Techniques for Solving Viscous Flow Equations with Massive Separation.- 5. Prediction of Post-Stall Flows on Airfoils.- 6. Turbulence Characteristics of Trailing-Edge Flows on Thick and Thin Hydrofoils.- 7. Computational Fluid Dynamics at NASA Ames Research Center.- 8. 3-D Composite Velocity Solutions for Subsonic/Transonic Flows.- 9. Calculation of Transonic Flows for Novel Engine-Airframe Installations.- 10. Calculation of Three-Dimensional Boundary Layers Including Hypersonic Flows.- 11. Supersonic/Hypersonic Euler Flowfield Prediction Method for Aircraft Configurations.- 12. Numerical Simulation of Separated and Vortical Flows on Bodies at Large Angles of Attack.- 2. Two- and Three-Dimensional Unsteady Flows.- 13. The Relevance of Unsteady Aerodynamics for Highly Maneuverable and Agile Aircraft.- 14. Experimental and Computational Studies of Dynamic Stall.- 15. A Critique of the Experimental Aerodynamic Data Base for an Oscillating Straked Wing at High Angles.- 16. On the Effects of Wind Tunnel Turbulence on Steady and Unsteady Airfoil Characteristics.- 3. Stability and Transition.- 17. Applications and Suggested Directions of Transition Research.- 18. Prediction of Transition on Airfoils with Separation Bubbles, Swept Wings, and Bodies of Revolution at Incidence.- 19. Transition in Hypersonic Boundary Layers.- 20. Transition Phenomena on Airfoils Operating at Low Chord Reynolds Numbers in Steady and Unsteady Flow.- 21. Disturbance Growth in an Unstable Three-Dimensional Boundary Layer.- 22. Experiments in Swept-Wing Transition.- 23. Experimental Transition and Boundary-Layer Stability Analysis for a Slotted Swept Laminar Flow Control Airfoil.- 24. Leading-Edge Contamination and Relaminarization on a Swept Wing at Incidence.- References.- Index of Contributors.

132 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,083
20221,871
2021923
2020979
20191,097
20181,002