二次元静止翼から発生する離散周波数騒音の研究 : 境界層中の乱れ分布の時刻歴変化の再現

抄録

Discrete tone noise generated in a uniform jet flow on a two-dimensional wing was investigated. Discrete tone noise is generated by a self-excited feedback loop formed by the acoustic field and the unstable boundary layer. In this work, the coherent flow velocity fluctuation in the boundary layer was reconstructed for the time sequential intensity distribution. From the time sequential flow fluctuation pattern, the following results were obtained. In the boundary layer on the suction side, the pattern of coherent velocity fluctuation intensity moved to the trailing edge and expanded its area with time. On the pressure side, a pseudo-sound wave was generated at the trailing edge, which shifted in the direction opposite that of main flow.