乱流境界層が流入する前方ステップ流れと発生する空力騒音の特性

抄録

In this study, aerodynamic noise generates from forward step flow with different flow velocities U₀ and step heights H were measured to investigate the characteristics of high-frequency wind noise generated from the Forward-Facing Step. The flow velocity was set to 0~50 m/s and the step height to H = 15, 30 and 45 mm. The aerodynamic noise was converted into sound pressure spectra by FFT to investigate their characteristics. To investigate the influence of the boundary layer thickness δ and step height H on the shear layer of the step, correlation measurements were performed on the shear layer to estimate the vortex scale. The results show that the high-frequency aerodynamic noise has a characteristic peak that is independent of the flow velocity. It is also confirmed that vortex scales which are nondimensionalized by step height generated in the shear layer at H/δ = 2 and 3 is similar.