Experimental Analysis of the Interaction between Streamwise Vortices and a High-Lift Airfoil

Abstract

The present paper presents experimental investigations of the interaction between streamwise vortices and a high-lift airfoil. A delta wing upstream of the high-lift airfoil generates two vortices, which proceed on the suction side of the airfoil and interact with the local flow field. The characteristics of the vortices resemble those of a nacelle strake vortex scaled to wind-tunnel dimensions. Measurements of the static pressure distributions and oilflow visualizations with and without the upstream located delta wing reveal the effect of the vortices on the high-lift airfoil. Furthermore, stereo-PIV measurements at different streamwise positions upstream of the high-lift airfoil and above the suction side show the development of the vortex characteristics. The investigations comprise variations of the angle of attack of the high-lift airfoil and the vertical position of the delta wing. The presence of the vortices clearly affects the flowfield of the high-lift configuration. Also, the characteristics of the vortex considerably change while proceeding downstream through an interaction with the flow field of the high-lift airfoil.