Similitudes for Acoustic Volumes: Analytical Models for the Response

The paper presents some updates about the search for exact and/or distorted similitudes to be applied to vibroacoustic models. These similitudes are aimed at obtaining prototypes which would be able to reproduce at convenient sizes the dynamic response of a fluid-filled elastic containers.Some experiences have been gained for the structural response involving panels and shells and some experimental evidences are already available. The attention is herein focused on the isolated volumes in view of reproducing the full coupled models. By adopting the modal approach, the main points are in the distribution of the natural frequencies, the damping conditions and the mode shapes. The incomplete (or distorted) similitudes and the related scaling laws will define the avatars which will not be replicas but will be able to replicate the original contents to some extent; they can be used for analysing the response at local scales by invoicing also some specific metrics, as the Hausdorff distance. The test-cases refer to a parallelepiped and cylindrical rooms which are represented by analytical solutions, but it is clear that the approach can be reformulated easily in generalised discrete coordinates scheme as for the finite element method.