抄録
When investigating the transmission noise like a vehicle interior noise, it is very important to consider the pressure fluctuations in the near acoustic field generated by air flow around a vehicle. However, since these pressure fluctuations are constructed by both acoustic and air flow fluctuations, it is difficult to separate and evaluate the levels of these two components individually. Therefore, in this paper, the wavenumber-frequency spectrum method was applied to analyze the flow field and the sound field around a square cylinder which was placed near a flat plate in order to examine the behavior of the pressure fluctuations in the near acoustic field. The statistical post processing method based on a time-space correlation was used to analyze acoustic and air flow fluctuations in a wavenumber domain. Thus, the differences in the convective velocity and the levels of sound and turbulent flow pressure fluctuations were investigated by changing the distance between the square cylinder and the flat plate.
