B132 対称翼から発生する離散周波数騒音の円柱後流による低減機構
2003 年 23 巻 Supplement2 号 p. 83-86
詳細
2003 年 23 巻 Supplement2 号 p. 83-86
The discrete frequency noise is generated from an airfoil in a uniform flow at small angle of attack to the free stream at moderate Reynolds number. The present experiment is conducted to find the reduction condition of discrete frequency noise by the influence of cylinder wake using a surface-flow visualization technique by shear-stress sensitive liquid crystal coating. Utilizing the color image analysis, the point of flow separation and reattachment is evaluated from the visualized images. It is found that the region of flow separation over the airfoil was fairly reduced by the influence of cylinder wake, where the suppression of discrete frequency noise was observed. The laminar boundary-layers over the airfoil seems to be shifted to a turbulent state by the influence of cylinder wake.
