Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Computational power against noise

13.10.2010
Computer model to calculate noise levels along the Swiss rail network

Working together with an international project team, Empa’s acoustic specialists have developed a computer model which allows them to calculate noise levels along the entire Swiss rail network.

The program describes how much sound is radiated and how it is attenuated. The results will one day show in high precision where residents are particularly exposed to noise and what abatement measures will be most effective in protecting them.

Goods trains move at night because during daytime the Swiss rail system is used to full capacity by passenger traffic. Unfortunately, it is goods trains which make the most noise – and they operate at exactly the time when most people want to sleep. If the policy of shifting goods transport from the roads to the rail network is to succeed, then goods trains must be made significantly quieter.

The Swiss Federal Office for the Environment (FOEN) therefore tasked a team of scientists, headed by Kurt Eggenschwiler of Empa’s Acoustics and Noise Control Laboratory, with the development of a computer model to simulate noise levels along the Swiss rail network. sonRAIL, the name given to the model, was intended to provide not just noise maps but to calculate the sound exposure of individual buildings.

The model thus identifies what remedial measures would be most effective. Federal and local authorities can therefore use sonRAIL to calculate sound levels around existing and planned railway lines and to evaluate the effectiveness of their countermeasures. A noise barrier reduces the rolling noise of the wheels, it is true, but does not protect against the drone of the ventilation system on the roof of a wagon. It is important, therefore, that the researchers do not just focus on wheel-rail noise, but view the problem as a whole, regarding the train as a complete system.

Measuring the noise from 15,000 trains
With this in mind, Eggenschwiler’s colleague, the acoustic expert Jean Marc Wunderli, together with an international team of scientists involved with the development of sonRAIL, have collected an enormous quantity of data. Between 2007 and 2009 they made measurements of some 15,000 train passings at eighteen locations. In doing so they identified sound sources at various heights along the train, allowing them, together with project partners from the Technical University of Berlin, to describe in detail the noise emission of individual train compositions.

The Empa researchers need this data to calculate how noise propagates in the direction of nearby residents. The intensity of train noise depends on many factors such as the kind of train passing, its speed, whether cliffs or buildings reflect the noise, the construction of the track bed, the local topography, and – not least – the weather. Only if all these parameters are taken into account in the computer simulation it is possible to quantify the noise pollution levels accurately.

To apply a model like sonRAIL for the calculation of acoustic emission levels along hundreds of kilometers of railway tracks and for the evaluation of noise propagation patterns at several tens of thousands of locations, a powerful computational system is required. At Empa the computer cluster «Ipazia» is available for this purpose, a system which not only provides high computational performance but more importantly, thanks to the cluster concept, allows parallel calculations on several processors.

40 processors working day and night
In the first practical «test» of the system, performed early 2010, the Empa acoustic specialists modeled noise levels along a section of the north-south rail corridor through Switzerland, an area of some 340 square kilometers in Canton Tessin. This area contained 50 kilometers of rail track, some 30,000 buildings, 17 noise barriers and involved some 17,200 individual receiver locations. 40 processors of the Empa computer cluster were approximately during a month in operation day and night, completing over 17 million individual point-point-calculations. Each calculation results in 14 frequency spectra, consisting of 20 one–third-octave bands, giving a total of over 1.4 billion individual values for the entire calculation area.
In the summer of the same year a comprehensive measurement campaign to validate the model took place on the northern side of the Gotthard tunnel. During a 24 hour period the Empa scientists, in cooperation with the company Prose AG, made measurements of rail traffic noise at the Federal Office of Transport’s (FOT) monitoring station in Steinen. Noise levels were evaluated at 7.5, 200, 500 and 900 meters from the source. The results showed that sonRAIL is capable to reproduce the measured values with high accuracy.

The researchers are now championing the case for their noise simulation model to become the standard to be used in Switzerland, and also that it be considered in the rest of Europe too. In addition they are planning to use the simulation for applications involving other kinds of noise, such as road traffic and shooting noise.

Dr. Jean-Marc Wunderli | EurekAlert!
Further information:
http://www.empa.ch

More articles from Studies and Analyses:

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>