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.

A proof of existence of perturbed steady transonic shocks via a free boundary problem

Abstract: We prove the existence of a solution of a free boundary problem for the transonic small-disturbance equation The free boundary is the position of a transonic shock dividing two regions of smooth flow Assuming inviscid, irrotational flow, as modeled by the transonic small-disturbance equation, the equation is hyperbolic upstream where the flow is supersonic, and elliptic in the downstream subsonic region To study the stability of a uniform planar transonic shock, we consider perturbation by a steady C1+ϵ upstream disturbance If the upstream disturbance is small in a C1 sense, then there is a steady solution in which the downstream flow and the transonic shock are Holder-continuous perturbations of the uniform configuration This result provides a new use of inviscid perturbation techniques to demonstrate, in two dimensions, the stability of transonic shock waves of the type that appear, for example, over the wing of an airplane, along an airfoil, or as bow shocks in a flow with a supersonic free-stream velocity © 2000 John Wiley & Sons, Inc

Numerical study of blowing and suction control mechanism on NACA0012 airfoil

Abstract: A jet with a width of 2.5% the chord length is placed on a NACA0012 airfoil’s upper surface simulating the blowing and suction control under Re =5 × 10 5 and angle-of-attack 18-deg conditions. Nearly 300 numerical simulations are conducted over a range of parameters (jet location, amplitude, and angle). The physical mechanisms that govern suction and blowing flow control are determined and analyzed, and the critical values of suction and blowing locations, amplitudes, and angles are discussed. The current successful large-scale numerical studies create a useful knowledge base for further exploration of multijet control system.

Design and experimental results for a flapped natural-laminar-flow airfoil for general aviation applications

Abstract: A natural-laminar-flow airfoil for general aviation applications, the NLF(1)-0416, was designed and analyzed theoretically and verified experimentally in the Langley Low-Turbulence Pressure Tunnel. The basic objective of combining the high maximum lift of the NASA low-speed airfoils with the low cruise drag of the NACA 6-series airfoils was achieved. The safety requirement that the maximum lift coefficient not be significantly affected with transition fixed near the leading edge was also met. Comparisons of the theoretical and experimental results show excellent agreement. Comparisons with other airfoils, both laminar flow and turbulent flow, confirm the achievement of the basic objective.