TURBULENT FLOW CONTROL WITH VORTEX GENERATORS AROUND A SYMMETRICAL AIRFOIL AT HIGH ATTACK ANGLES
Hocine Tebbiche, Mohammed Saîd Boutoudj (DOI: 10.24874/jsscm.2019.13.02.06)
Abstract
The flow on the upper surface of NACA 0015 airfoil is subject to an adverse pressure gradientThe flow on the upper surface of NACA 0015 airfoil is subject to an adverse pressure gradientwhen the incidence increases. This leads to the boundary layer separation which causes losses inthe aerodynamic performances. Control using Vortex Generators (VGs) is a simple passive meanused to delay or eliminate the flow separation from the wall.
The two main objectives of the experimental work performed consist in the optimization byexperimental design method "DoE" of a new VGs configuration, inspired by Lin's one, by varyingits different geometrical parameters. A comparative efficiency study of the two VGsconfigurations (Lin's VGs, modified VGs) on aerodynamic performances was then undertaken atdifferent Reynolds numbers.
In addition to the significant improvement in lift around 22%, the study resulted in a dragreduction of approximately 16% and a stall delay of two degrees. The results were also comparedto a three-dimensional numerical simulation (3D-RANS) and showed good agreement. The CFDresults 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.
