Noise Source Identification in a 2D Cavity Based on Inverse Finite Element Method

Abstract

The identification of noise sources in enclosures proves to be particularly difficult in the low-frequency range, because the emerging standing wave field does not allow direct conclusions as to the location of sources. This paper presents an approach to reconstruct sound pressure and particle velocity on the boundary, based on an inverse finite element method (IFEM). This procedure requires sound pressure measurements in the interior first. In a second step, these data are associated to the nodes of an acoustic finite element model of the cavity. If all sources are located on the boundary, the equation system resulting from the numerical model can be re-sorted in such a way that the boundary values can be reconstructed. The IFEM is verified by a two-dimensional simulation. Including an energy-minimizing solution norm, performance on arbitrarily shaped boundaries is improved. Finally, the IFEM is applied in a two-dimensional laboratory experiment. By means of regularization techniques, a loudspeaker included in the boundary of a test facility can be identified.