気流に平行に磁力支持された円柱の空力特性

抄録

Aerodynamic characteristics of a cylinder with a fineness ratio 1.68 in axial flow were examined experimentally using a magnetic suspension and balance system. Sting support interferences were also estimated by use of a dummy sting located at the back of the cylinder. Flow field structures were measured using particle image velocimetry. There were little influences of the rear sting on a drag coefficient for the Reynolds numbers from 6.7 × 10⁴ to 1.9 × 10⁵. In addition, over the entire measurement range, the drag and base pressure coefficient depended little on the Reynolds number. On the other hand, it was revealed that the rear sting made the flow field non-axisymmetric. In the case with the sting, the streamwise velocity at the rear of the cylinder was a little slower with the distance from the sting, while the turbulence intensity became much stronger. The similar features were observed near the cylinder side surface. Furthermore, high values of the turbulent fluctuation perpendicular to the freestream direction were observed near the trailing edge of the cylinder. It suggested that the rear sting had stronger influences on the flow away from the sting and the effects spread upstream.