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Shock and Vibration
Volume 13, Issue 4-5, Pages 219-232

A New Technique to Identify Arbitrarily Shaped Noise Sources

Roberto A. Tenenbaum1 and Marcelo Bruno S. Magalhães2

1Instituto Politécnico do Rio de Janeiro, IPRJ/UERJ, Rua Alberto Rangel, s/n, Vila Nova, 28630-050, Nova Friburgo, RJ, Brazil
2FSAO Virtual Series Department, Ford Motor Company, Brazil

Received 19 July 2006; Revised 19 July 2006

Copyright © 2006 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Acoustic intensity is one of the available tools for evaluating sound radiation from vibrating bodies. Active intensity may, in some situations, not give a faithful insight about how much energy is in fact carried into the far field. It was then proposed a new parameter, the supersonic acoustic intensity, which takes into account only the intensity generated by components having a smaller wavenumber than the acoustic one. However, the method is only efective for simple sources, such as plane plates, cylinders and spheres. This work presents a new technique, based on the Boundary Elements Method and the Singular Value Decomposition, to compute the supersonic acoustic intensity for arbitrarily shaped sources. The technique is based in the Kirchoff-Helmholtz equation in a discretized approach, leading to a radiation operator that relates the normal velocity on the source's surface mesh with the pressure at grid points located in the field. Then, the singular value decomposition technique is set to the radiation operator and a cutoff criterion is applied to remove non propagating components. Some numerical examples are presented.