数値音響解析によるボックスファンから発生する空力音の予測

抄録

The far-field sound generated aerodynamically from a box fan is predicted by a computational aeroacoustics (CAA). The method is composed of the large eddy simulation of the incompressible fluid flow that computes the transitional boundary layer on the fan blades and the wake and the acoustical simulation that takes the effects of the reflection of the sound radiated from the fan into account. In particular, the influence of the Sub-grid scale (SGS) model on the computed flow field and that of the position of the dipole sound source on the radiated sound are investigated. The far-field sound spectra computed by the above-mentioned method are compared with the measured ones as well as that computed by the Curle’s equation. It is found that the Dynamic Smagorinsky Model predicts the far-field sound more accurately than the Standard Smagorinsky Model. The position of the dipole source affects remarkably the far-field sound.