CPL - Chalmers Publication Library

# On the Directivity of Railway Noise Sources

Xuetao Zhang (Institutionen för bygg- och miljöteknik, Teknisk akustik, Vibroakustik)
Göteborg : Chalmers University of Technology, 2007. ISBN: 1652-9146.- 90 s.
[Licentiatavhandling]

This dissertation deals with the directivity of railway noise. The directivity of railway noise is of particular importance when we have high-rise buildings close to the track, tunnel openings, partial barriers, or when we calculate the maximum sound pressure level during a pass-by based on the sound power level of the different sub-sources of a train. On the other hand, directivity is a part of source description. The directivity of the different sub-sources of a train has been studied systematically by carrying out new measurements, collecting relevant information from the literature and modelling the physical processes. The focus has been on railway rolling noise from wheels and track but both railway traction noise and aerodynamic noise are also dealt with. First the individual sub-sources are studied and then the sound pressure level contributions from each of these sources are combined to yield the directivity of a whole train. In general, the directivity of a whole train is both distance and speed dependent. Moreover, high speed source motion can affect the directivity dramatically. All these results are summarized into equations practical to use for engineering applications.

Nyckelord: directivity, railway rolling noise, railway aerodynamic noise, railway traction noise, moving source, the Doppler factor, sound emission time, sound immission time, line source, equivalent source line, De-Dopplerization

Including 3 publications: (1) To determine the horizontal directivity of a train pass-by (in03_627), Inter-Noise 2003, Jeju, Korea, August 25-28, 2003. (2) Directivity of Railway Noise Sources, Journal of Sound and Vibration 293 (2006) 995 - 1006. (3) Directivity of Railway Rolling Noise, the 9th International Workshop on Railway Noise, Munich, Germany, September 4-8, 2007.

CPL Pubid: 64898

# Institutioner (Chalmers)

Institutionen för bygg- och miljöteknik, Teknisk akustik, Vibroakustik (2005-2017)

# Examination

Datum: 2008-01-22
Tid: 10:00
Lokal: Room VH, V-building, Chalmers
Opponent: Prof. Dr. Jens Nielsen