The Numerical Prediction of the Aerodynamic Noise of the TGV POS High-Speed Train Power Car

For a high-speed train operating at 300km/h or more, the aerodynamic noise, which is induced by the pressure fluctuations of the air, reaches similar levels to the rolling noise, which is due to contact between the rail and wheel. For this reason, the study of the noise generated by the flow around the train is of great interest for the constructors and operators of high-speed trains. Although the main noise sources are now well identified, their localization is so far mainly based on experimental techniques using acoustic array measurements, applied either on small-scale models in a wind tunnel or on full-scale passing trains. Nonetheless, the numerical prediction of the aerodynamic noise is becoming more and more of a practical possibility, as the need is emerging for proper integration of technical solutions and optimizations at an early stage of design of new rolling stock. In this study, the aerodynamic noise generated by the power car of the TGV POS high-speed train is considered. This generation of TGV is named POS for Paris Ost-Frankreich Süd-Deutschland as it has been dedicated to connect Paris to the East of France (Strasbourg) and the South of Germany (Stuttgart, Munich). It has been introduced on the French and German high-speed network in 2007, where the operational speed has been increased from 300km/h to 320km/h (on French East-European line). For the two main reasons of the introduction of new rolling stock and the increase in speed, the aerodynamic noise is less well known and is expected to be more significant. A numerical study has been carried out to identify the sources of the noise and to quantify their level. Some results will be presented here. In order to obtain results of a high level of quality, a very detailed geometry was used, and the unsteady simulations were carried out at full scale. The complexity of the real geometry and the consideration of all parts and elements of bogie or pantograph frames enabled the influence to be determined of several shape modifications or of the integration of fairings on the level of aerodynamic noise. This gives some clues for solutions in terms of noise reduction. Among all the solutions tested, two examples have been selected and are presented in this paper.