The wing three-dimensional effects on wavy leading edge performance

Abstract

© 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.A distinct wavy leading edge performance for finite wings can be expected in comparison to the infinite wing, due to the differences in geometry and flow conditions. An infinite span wing, unlike a partial span model, has a unique local Reynolds number, sweep angle, thickness and camber. In addition, it is not subjected to the wing tip phenomenon which changes the pressure coefficient along span, and, as consequence, the adverse pressure gradients. These differences on the flow over finite and infinite span geometries cause differences in tubercle performance, which have motivated some works, in order to investigate the influence of flow three-dimensionality on wavy leading edge performance. However, there are lack of works that evaluate the effects of the wing’s three-dimensional on flow topology of the wavy leading edge and their consequences in performance. The aim of this study is to investigate the effects of the wing’s three-dimensional flow on wavy leading edge phenomena at low Reynolds number. Experimental investigations were carried-out modifying geometric parameters of the wing planform (taper ratio and sweep) in order to understand the effects of these parameters on wavy leading edge phenomena. The tests are conducted for pairs of models with and without tubercles. A pair of two-dimensional models (NACA 0020) and four pairs of finite-wing models with taper ratios of 0.5 and 1, and sweep angles of 0º and 30º were tested. The experimental investigation was based on evaluation of force measurements (lift and drag) and flow visualizations (oil and mini-tufts). Additionally, the Reynolds number effects were also investigated by evaluating the wavy leading edge characteristics at Reynolds number 80,000 and 200,000.