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Sound propagation at obstacles |
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 The description of the sound field over impedance surfaces (grounds, road surfaces etc.) in the surrounding area of obstacles (sound-reflecting, absorbing and / or diffuse reflecting acoustic screens, walls etc.) requires consideration of different effects. Modeling the emission sound source to be examined (location, strength, directional characteristic) is important as well.
(see Publications 2007 and 2008)
Our investigations include the following effects :
- Air absorption according to ISO 9613
- Ground-borne reflection (application of "Weyl-van der Pool" model)
 - Sound propagation over impedance planes with discontinuities (modification of the Fresnel-zone model of Hothersall)
- Sound diffraction at acoustic screens with absorbing surfaces (determination according to Hadden and Pierce)
- Diffuse sound reflection at structured surfaces (computation according to NORD 2000)
- Reflection at the upper edge of obstacles (according to the Fresnel-zones model of NORD 2000)
- Directional characteristic of the sound source (e.g. application of a microphone array, see Traffic noise/Sound emission of vehicles)
- Incoherence by sound diffraction by means of wind and temperature profiles as well as atmospheric turbulence according to SonRoad
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Top: Messung des Schallabsorptionsgrads (des Reflexionsfaktors) in situ
Unten: Schallausbreitung ohne und mit Lärmschutzwand numerisch berechnet mit BEM-Methode
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