Speaker
Description
In the Netherlands, two models are used for official environmental sound propagation calculations: the national MRG model (similar to the ISO 9613-2 model) and the European CNOSSOS model. A key difference between these models is the calculation of ground attenuation, which can lead to differences of up to 10-20 dB in certain octave bands. Such differences can have a significant impact on the outcomes of environmental noise assessments. The observed discrepancies therefore raise important questions about the validity of each model.This study provides a systematic comparison and validation of the ground attenuation calculation method of both models by combining numerical simulations with field measurements. A Finite Element Method (FEM) is used to generate numerical benchmark data under various ground types and meteorological conditions. To validate these simulations, a measurement campaign is conducted at an airport, where a controlled artificial sound source is used to measure sound propagation simultaneously at multiple distances (up to 500 m) and heights over both acoustically hard and soft surfaces. Ground impedance and meteorological parameters are also recorded. Results from the MRG/ISO and CNOSSOS models are compared with both FEM simulations and experimental data.By providing a comprehensive benchmark, this research contributes to improved reliability of sound propagation models widely used in environmental acoustics. The presentation will discuss some background, numerical approach, and experimental findings.