Localisation and characterisation of TGV trains noise sources with acoustical array measurements

摘要

In the railway domain, the increase of commercial train speed leads to an amplification of the pass-by noise. Around 320 km/h, the contributions of the aerodynamic noise and the rolling noise are in the same order of importance. Parametric studies with pass-by noise prediction softwares like VAMPPASS (developed in SILENCE IP project) provide the best combination of solutions to reduce the pass-by noise. In this software, the definition of the sources is the main difficulty. Measurement using array processing is the only way to characterize the sources during pass-by even though the extraction of the sources characteristics remains difficult. Therefore, SNCF has carried out a measurement campaign on TGV trains to identify and characterize their acoustic sources. The measurement campaign, the acoustic array and the corresponding processing are presented. Characterization of several sources is discussed. Since the rolling noise remains a major source at speeds higher than 300kph, it has to be properly modeled in simulations softwares. Therefore, in addition to the test train, a large amount of commercial trains were measured and each of their axles was characterized in terms of sound pressure level magnitudes and spectra. A statistical study of those results enables us to come up with a convenient noise model for power and carrier axles.