Turbulent Flow Control With Vortex Generators Around a Symmetrical Airfoil at High Attack Angles

Abstract

The flow on the upper surface of NACA 0015 airfoil is subject to an adverse pressure gradient when the incidence increases. This leads to the boundary layer separation which causes losses in the aerodynamic performances. Control using Vortex Generators (VGs) is a simple passive mean used to delay or eliminate the flow separation from the wall. The two main objectives of the experimental work performed consist in the optimization by experimental design method "DoE" of a new VGs configuration, inspired by Lin's one, by varying its different geometrical parameters. A comparative efficiency study of the two VGs configurations (Lin's VGs, modified VGs) on aerodynamic performances was then undertaken at different Reynolds numbers. In addition to the significant improvement in lift around 22%, the study resulted in a drag reduction of approximately 16% and a stall delay of two degrees. The results were also compared to a three-dimensional numerical simulation (3D-RANS) and showed good agreement. The CFD results highlighted a clear improvement in the momentum thickness along the airfoil's upper face, particularly a rate of 44.44% at 40% of the chord length.

The Effect of Vortex Generators on Spray Deposition and Drift from an Agricultural Aircraft

“…This jet-age technology provides improved aileron response, reduced turning time, a 7% reduction in stall speed, and reduced landing and take-off roll [21,22]. Tebbiche and Boutoudj [23] designed and studied VGs in a wind tunnel and found that they decreased drag by about 13% at a 15 • stall angle, and that drag reduction would result in increased fuel economy and reduced exhaust gas and aircraft noise. Vignesh et al [24] reported that the VG in a Clark Y type airfoil would enhance the payload and take-off as well as reduce landing distances for short runways and produce desirable changes in the stall characteristics of an airfoil wing.…”

Simulation d’un écoulement d’air projeté sur un profil de pale d’éolienne avec générateurs de vortex

“…Les résultats obtenus ont montré qu'il y a une réduction de la force de traînée jusqu'à 10%. [7] Dans ce travail, une simulation numérique a été faite, à l'aide du code de calcul -Fluent-, de l'écoulement d'air sur une pale d'éolienne 'FX-63-137' dans le but d'étudier le comportement dynamique autour du profil en absence et en présence des générateurs vortex (GV). Les effets de l'angle d'incidence du vent et aussi de la position des générateurs de vortex par rapport au profil ont été examinés.…”