Unsteady wall pressure characteristics of a 90 degree elbow in high Reynolds numbers

高レイノルド数における90エルボ管の非定常壁面圧力特性

岩本 幸治*; 山野 秀将   

Iwamoto, Yukiharu*; Yamano, Hidemasa

曲率が内径と一致(125mm)する90エルボ管の壁圧計測を行った。ここで得た規格化圧分布変動とレイノルド数3,250,000における白石ら(2006)の結果とは動圧の0.02以内で一致したことを示した。ストローハル数0.5の最大強度は白石らが実験で設定した(2011年山野ら)使用と定性的に一致し力学的相似則が振動に関して適用できることを示唆した。圧力変動の相互相関はストローハル数0.5の圧力変動は平面波としてバルク速度で伝播することを示した。

Wall pressure measurements were conducted for a 90 degree elbow of which the axis curvature coincided with its inner diameter (125 mm). Results showed that distributions of fluctuating normalized pressures obtained here and those made by Shiraishi et al. (2006) for the Reynolds number of 3,250,000 coincided within 0.02 of the dynamic pressure. The peak intensity having the Strouhal number of 0.5 was quantitatively in accordance with that of the data obtained in the experimental setup that Shiraishi et al. used (Yamano et al., 2011), suggesting that the law of dynamical similarity could be applied with regard to this oscillation. Cross correlations of pressure fluctuations showed that the pressure fluctuation having the Strouhal number of 0.5 propagated as a planar wave with the bulk velocity.