The objective of this paper is to separate the aeroacoustic and vibroacoustic contributions in the radiated sound. For this purpose the authors study the mechanisms of noise generation at a simplified model of a car's underbody. They mount a flexible rectangular plate into a rigid surrounding plate, which is then placed in a wind tunnel in parallel to the main flow direction. A square cylinder may be optionally mounted upstream of the flexible plate in order to model a strut. This setup generates noise by the same mechanisms as an underbody. The authors measure the sound pressure with a microphone and, simultaneously, the normal deflections of the plate with a laser scanning vibrometer. On the basis of these data they conduct Finite Element Method (FEM) simulations in order to compute the vibrational sound at the position of the microphone. Subsequently, they estimate the contribution of the vibrational sound by comparing it to the measured data. First the experimental setup is described. The next section will deal with the Finite Element scheme, that is used to conduct the simulation. After that the results of the experiments and the simulations will be discussed in detail.
Separation of aero- and vibroacoustic noise from a flexible structure
2009
4 Seiten, 9 Bilder, 4 Quellen
Conference paper
English
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