New Techniques in Noise Prediction

Noise prediction methods must include the mathematical description of many physical phenomena influencing sound propagation. More scientific based methods approximate the solution of the wave equation with given boundary conditions, while the engineering methods simulate the wave propagation by geometrically defined rays. The first mentioned scientifically based methods are powerful to investigate certain effects as propagation in a layered atmosphere or diffraction over a complex barrier in a simple and clear defined environment, while the engineering methods are clearly superior in realistic complex scenarios like industrial facilities or built up areas in cities with thousands of traffic sources. The techniques applied have been improved in the last years and an example of such an improvement is presented and explained.