低レイノルズ数流れにおける低アスペクト比翼まわり流れ場のPIVを用いた可視化

抄録

The spanwise cross-sectional flow fields around a NACA0012 wing with an aspect ratio of 1.0 at a Reynolds number of 2.5×10⁴ are visualized in a towing tank. The PIV visualization is conducted for the region above the upper surface. The results qualitatively show the flow field including a pair of the tip vortices, their size and position. Furthermore, another large vortex system is found in the region between a pair of the tip vortices. At angle of attack 30° or more the each vortex of the latter pair is spinning the opposite way relative to the counter part of the tip vortex pair. It is thought that the interaction between these vortices leads to the distinctive feature on the aerodynamic characteristics of low-aspect-ratio wings.