Acoustics simulation in urban spaces
With its focus to protect the public from harmful noise pollution, the 3D Acoustics project has led to a fast new method for calculating how noise spreads. Using physics-based models, this method simulates the 3D propagation of noise in an urban context.
About the project
Today’s established methods for calculating three-dimensional (3D) sound propagation still have only limited application possibilities and cannot physically represent the actual sound path. Because these methods are rule-based, actual facts or objects are simplified so that the results are rough approximations.
Furthermore, reflections are hardly considered at all. If, however, accurate and special results are required, it is possible to calculate all physical effects with the finite element method (FEM). The drawback here is that very large computing power is required, especially for models with large extensions.
To solve this problem, inuTech is developing a novel and fast calculation method that simulates 3D sound propagation in an urban context. This so-called Dynamic Energy Analysis (DEA) approach will help answer complex acoustic questions based on physical models, which in turn will better protect the population from harmful noise pollution.
Specifically, the DEA approach consists of a radiation method (Local Ray Tracing) in a rough grid of the area under consideration. Within the scope of the project, this approach will be extended to 3D problems.
This allows the precise analysis of models with large extensions at a significantly reduced computational effort. The Fraunhofer Institute for Building Physics (IBP) contributes the scientific framework, which includes the physical laws of reflection, transmission, refraction, and diffraction. These are the basis for developing mathematical procedures.
Virtual City Systems is integrating this novel calculation method into the VC Map as an independent application. City model sections are processed as networked air-volume models, enriched, and solved with all relevant acoustic properties, such as reflection coefficients for facades.
The visualizations of the results in the map allow authorities and planners in acoustic urban design to explore forward-looking possibilities. For example, sound-absorbing effects on a façade or other structures can be considered for the optimization of sound insulation measures, a novelty that existing methods do not offer.