Calculation of Multiple Diffraction in a Downward Refracting Atmosphere With Ray-Based Engineering Models
With engineering models like Harmonoise, NMPB:2008 or CNOSSOS-EU:2015 favorable propagation conditions are taken into account with curved ray paths. In all these models, the insertion loss caused by a barrier is assumed to be a function of the path length difference between the curved ray over the diffracting edge and the direct curved ray connecting source and receiver in absence of the barrier. With many screening objects – a frequently occurring case in noise-mapping for built-up areas – NMPB:2008 and CNOSSOS-EU:2015 proceed by, in a first step, selecting the relevant diffracting edges with the so-called rubber-band-method and, in a second step, calculating the path length difference by connecting these edges with curved ray segments. Practical experience has shown that this method is flawed and may even produce level-increases if a new barrier is inserted. To empower these engineering methods to properly handle multiple diffraction in downward refracting atmospheric conditions an improved method was developed and tested. The strategy is analogous to the rubber-band-method; it replaces straight segments with arcs and logically extends the concept of a "convex envelope". A step-by-step procedure ready for implementation in software is presented and its performance is demonstrated.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: January 1, 2019
More about this publication?
- Acta Acustica united with Acustica, published together with the European Acoustics Association (EAA), is an international, peer-reviewed journal on acoustics. It publishes original articles on all subjects in the field of acoustics, such as general linear acoustics, nonlinear acoustics, macrosonics, flow acoustics, atmospheric sound, underwater sound, ultrasonics, physical acoustics, structural acoustics, noise control, active control, environmental noise, building acoustics, room acoustics, acoustic materials, acoustic signal processing, computational and numerical acoustics, hearing, audiology and psychoacoustics, speech, musical acoustics, electroacoustics, auditory quality of systems. It reports on original scientific research in acoustics and on engineering applications. The journal considers scientific papers, technical and applied papers, book reviews, short communications, doctoral thesis abstracts, etc. In irregular intervals also special issues and review articles are published.
- Editorial Board
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Information for Advertisers
- Online User License
- Ingenta Connect is not responsible for the content or availability of external websites