Control of Flow Separation Using Self-Supplying Air-Jet Vortex Generators

Abstract

Wind-tunnel experimental investigations were conducted to investigate the use of conventional outsupplying and proposed self-supplying air-jet vortex generators to delay flow separation over an NACA 0012 airfoil. The conventional air-jet vortex generators were supplied with the air from an external compressor, and proposed self-supplying generators got the air from the overpressure region situated in the nose part of the airfoil lower surface. The lift, drag, and pitching moment for the smooth airfoil equipped with air-jet vortex generators were determined based on the pressure distribution measurements. The experimental tests were carried out in both the low-speed wind tunnel (M=0.05-0.1) with the airfoil model of 0.5-m chord length and the high-speed wind tunnel (M = 0.1-0.85) with the airfoil model of 0.18-m chord length. In the high-speed wind tunnel, the influence of using only the self-supplying air-jet vortex generators was tested. It was found that using both types of air vortex generators can delay the flow separation on the airfoil, which leads to the increase of both the lift coefficient and the critical angle of attack.