Visualization and PIV study of wing-tip vortices for three different tip configurations

• Published in: Aerospace science and technology 2012-01, Vol.16 (1), p.40-46
• Main Authors: Sohn, Myong Hwan, Chang, Jo Won
• Format: Article
• Language: English
• Subjects: Aerodynamics; Angle of attack; Applied fluid mechanics; Exact sciences and technology; Fairings; Fluid dynamics; Fluid flow; Fundamental areas of phenomenology (including applications); Instrumentation for fluid dynamics; Particle Image Velocimetry (PIV) Measurement; Physics; Smoke-wire visualization; Visualization; Vortices; Wing-tip configuration; Wing-tip vortex; Winglets; Wings (aircraft)
• ISSN: 1270-9638; 1626-3219
• DOI: 10.1016/j.ast.2011.02.005

The planform, profile, and cross-sectional views of the wing-tip region of a half-wing model with an aspect ratio of 3.2 and three different wing configurations, namely, square-cut, simple fairing, and Whitcombʼs full winglet wing-tip, were visualized at various angles of attack using smoke-wire visualization technique. Visualization pictures clearly show that the wing-tip vortices at different angles of attack and wing-tip configurations had distinct formation and structure characteristics. A comparison of simple fairing and Whitcombʼs winglet configurations shows that the wing-tip vortices of the Whitcombʼs winglet configuration were reduced in strength and displaced outboard and upward, at least in the near-wake region. This resulted in an increased lift-to-drag ratio for the Whitcombʼs winglet configuration. The changes in the wing-tip vortex characteristics and the improved aerodynamic performance of the winglet were confirmed by Particle Image Velocimetry (PIV) measurements of the cross-flow velocity of the wing-tip trailing regions and the force measurement of the model.