Acoustic wall pressure simulation in a train using Boundary Element and Beam tracing methods

One of the main parameters that define the comfort of a train is the noise. There are several numerical methods to perform airborne interior noise predictions, one key input of this process is the acoustic pressure around the train coming from the external acoustic sources. Many times for this wall pressure an experimental database is created from measurements. The main problems of this method are the availability for tests, the cost and the impossibility to take into account architectural changes of the new projects compared with the measurement ones. To overcome these limitations, it is possible to replace the expensive field tests with calculations. In this study we present the assessment of the results of pressure field around a railway vehicle obtained with two computation techniques (Boundary Element Method and Ray-tracing) compared with experimental values measured on an existing train with artificial sources and real operating conditions. Results with artificial sources are promising with enough accuracy for industrial applications, on the other hand for real operating conditions the problem is a challenge because the complexity of how real sources are simulated: location, distribution, etc... Part of the results shown is funded by the European Union within the Shift2Rail project FINE1.