Vortex Creation and Wing-Tip Geometry Dependencies

Abstract

This study presents experimental 3C-PIV investigations of the vortex topology at the wing-tip. The aim is to identify geometrical aspects of the wing-tip, which exert dominant influence on the production of the axial velocity component. Different wing-tip shapes are considered. Typical rectangular round and flat shapes as well as shapes, which feature a rounding of the layout are used. Special focus is placed upon vortex creation at the wing-tip, where vorticity is accumulated by primary and also to some extent by secondary vortices. The evolution and gradual enhancement of the radial circulation profile is displayed. A rounding of the side of the tip results in a more intensive vortex. An increasing rounding of the layout has the opposite effect. Correlation of vortex topology and therefore wing-tip shaping are shown. In a second step a calculation and analysis of the real, inviscid, as well as the viscid axial velocity component at the center of the vortex is performed. Therefore the geometrical features of the tip can be related to the production and suppression of the axial velocity component during the vortex creation phase at the wing-tip.