PRELIMINARY STUDY ON THE NEAR-FIELD WAKE OF NACA0012 WINGTIP VORTICES UNDER LOW-SPEED CONDITIONS

Abstract

The wingtip vortex is a complex aerodynamic phenomenon that impacts the operational safety of aircraft. Previous studies have indicated the occurrence of an accelerated axial flow (jet-like flow) in the vicinity of the vortex core. This study focuses on elucidating the characteristics of this accelerated flow as well as the tangential velocity distribution and circulation of the wingtip vortex. Experimental measurements were performed on a NACA0012 wing model featuring a square-cut flat tip, with data acquired at a crossflow plane 1.0c downstream of the trailing edge. The results indicate that at an angle of attack of 10º, the maximum axial velocity at the vortex core reached approximately 1.2U showing good agreement with previous studies. The measured vortex structure exhibited asymmetry in its tangential velocity distribution, reflecting the ongoing roll-up process of the wingtip vortex. The spatially averaged tangential velocity and circulation profiles demonstrate strong agreement with the theoretical Lamb-Oseen model.