Vortex interaction on a LEX configuration

Flow visualization experiments were conducted in a water channel and a low-speed wind tunnel at Reynolds number of 1.54 × 10⁴ to 1.2 × 10⁵ for a leading-edge extension model, which is referred to as a NASA TP-1803 model in this study. In addition, particle image velocimetry velocity measurements were taken in the water channel to obtain the quantitative information about the three-dimensional velocity field over the strake and wing surfaces. The results obtained at low, medium and high angles of attacks represent three distinct cases of interaction between the strake and wing vortices. Namely, at α = 5^o and 10° the strake and wing vortices were developed over the wing surface without significant interaction noticed; at α = 20°, the strake vortex strongly interacted with the wing vortex in an intertwining manner, which was sensitive to Reynolds number; at α = 30°, the breakdown of the strake vortex took place close to the junction of the strake and the wing; thus, the interaction of the strake and the wing vortices appeared to be less significant than the case of α = 20°. Graphic abstract: [Figure not available: see fulltext.]