Abstract
An experimental investigation was performed on the effect of fractal endplates on the wingtip vortex of a NACA 0012 semi span wing at a Reynolds number of 2 x 105. The endplates were obtained by introducing three different fractal patterns. Constant temperature anemometry and stereoscopic particle image velocimetry were employed to assess both the local flow properties as well as the spatial organization of the wingtip vortex. The results show that the introduction of a fractal endplate strongly affects both the geometry and the turbulence features of the vortex. In particular, it is found that the fractal geometry weakens the vortex by spreading the turbulent kinetic energy over a broader range of frequencies. We relate this loss of coherence to a faster dissipation of the vortex, thus paving the way to the employment of fractal endplates to reduce the hazard associated to such flow features.