Identification of the rail radiation using beamforming and a 2 D array

Florent Le Courtois , Jean-Hugh Thomas (1) , Franck Poisson (2) , Jean-Claude Pascal (1)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans
2 SNCF - DIR

Rolling noise is the major contribution to train pass-by noise. Array processing provides noise maps of the source location on the train. The rolling noise contribution is located around the wheels at 2 kHz on those maps and the rail is not well identified as a source, whereas models, like TWINS, estimate that its acoustical contribution can be in the same order of magnitude as the wheel contribution in the medium frequency range (1000 Hz). Flexion wave causes the rail to radiate in privileged direction due to fluid structure interaction. Beamforming processing identifies this acoustical radiation only under particular conditions, which is an explanation to the underestimation of the rail radiation on the global noise map of the train. This article presents a simple radiation model of the rail and the simulation result provided from beamforming processing to localize the theoretical radiation angle. An experimentation is performed using the classical 2 D adapted for train pass-by source localisation. The rail is excited in the vertical direction using a shaker. The radiation angle is not retrieved: the use of the classical array is not relevant to measure the radiation angle.

Mots clés: rail; beamforming; array

Domaines: Acoustique [physics.class-ph]

Florent Le Courtois, Jean-Hugh Thomas, Franck Poisson, Jean-Claude Pascal. Identification of the rail radiation using beamforming and a 2 D array. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810921⟩