Source identification in small spaces using field separation method: application to a car trunk

Alexandre Garcia (1) , Yacine Braïkia (1) , Christophe Langrenne (1) , Eric Bavu (1) , Manuel Melon (1)

1 LMSSC - Laboratoire de Mécanique des Structures et des Systèmes Couplés

Acoustic holography is a powerful tool for the localization and ranking of sound sources. However when dealing with non-anechoic spaces, classical methods have to be modified to take into account reflections on the walls of the testing room and, if necessary, the field radiated by secondary sources. In this paper, the field separation method is used to overcome these problems. The method used here consists in measuring the acoustic pressure on a double layer half-sphere array which base is lying on the surface of interest. Then, by using spherical harmonic expansions, contributions from outgoing and incoming waves can be separated if the impedance of the tested surface is high enough. Simulations on simple configurations and measurements on a car trunk mock-up are first presented. For the measured cases, the double layer array used is made-up of 2*36 carefully calibrated microphones. Comparison with results obtained with double layer SONAH are also shown. Finally, results obtained with a real car on a roller bench are reported.

Mots clés: Confined space; Spherical harmonics; Car; Holography

Domaines: Acoustique [physics.class-ph]

Alexandre Garcia, Yacine Braïkia, Christophe Langrenne, Eric Bavu, Manuel Melon. Source identification in small spaces using field separation method: application to a car trunk. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810827⟩