Prediction of the Aerodynamic Sound Power Level of a High Speed Train Bogie Based on Unsteady FW-H Simulation

Aerodynamic noise is generated by interaction of the air flow with an object and by the turbulent flow itself. In railways it becomes a significant noise source for speeds above 250 kph and major areas of noise generation on (high speed) trains are the train head, the leading and second bogie, the pantograph and the gaps between coaches. This paper presents a numerical simulation approach based on CFD/CAA techniques aiming to estimate equivalent sources for aerodynamic noise of different components of SNCF’s TGV high speed trains. The approach is based on an unsteady DES flow simulation combined with the Ffowcs-Williams and Hawkins (FW-H) analogy for the acoustic part. In order to develop the method a symmetric and full model are implemented and the leading bogie was selected as an application case. Results of this simulation, in terms of sound power and directivity, are already used by SNCF noise experts in order to estimate pass-by noise levels of TGV high speed trains. In the future other noise source will be simulated and mitigation devices such as deflectors will be tested numerically.