自動車周りの流れに起因する疑似音場に関する研究

抄録

In order to study the mechanism of the vehicle interior noise induced by the flow around the automobile, the near sound field around the rearview mirrors and the A-pillars is usually focused. As the difference in scale and intensity, in the near sound field, the pressure fluctuations related to the hydrodynamics and the acoustics can be considered as two different phenomena. After dividing these two phenomena by decomposition method, as the pressure fluctuations affect the interior noise through the glass transmission, the pseudo sound should not be neglected. By calculating the Ligthill Equation (LE) to show the sound field, the pseudo sound can be observed in the near sound field. On the other hand, the Acoustic Perturbation Equation (APE) can be used to show the sound field without pseudo sound. By comparing the results of LE and APE, we can evaluate the pseudo sound quantitatively. At the same time, by performing the wavenumber-frequency spectrum analysis, flow field, sound field, pseudo sound, apparent sound can be distinguished in different wavenumber regions and their contribution to the interior noise can also be evaluated.