吸音ダクトによるファン騒音の低周波域低減

抄録

We attempted to elucidate the mechanism of fan noise reduction at low frequencies below 1000 Hz through cavity and acoustic treatment. The experimental data showed that significant reductions were obtained at several frequencies while no reduction was obtained at others. By the numerical analysis conducted in this paper, it might be concluded that such phenomena were caused by the longitudinal mode of sound waves travelling in the cavity.