A ray model for hard parallel noise barriers in high-rise cities

Area of Science:

• Acoustics
• Urban planning
• Environmental engineering

Background:

• Noise barriers are essential for mitigating urban noise pollution.
• Accurate prediction of noise barrier performance in complex urban environments is challenging.
• Existing models may not fully capture acoustic phenomena like diffraction and reflections in street canyons.

Purpose of the Study:

• To develop and validate a ray model for predicting the insertion loss of hard parallel noise barriers.
• To investigate the impact of geometrical acoustics, including diffraction and multiple reflections, on sound pressure levels.
• To assess the model's accuracy against wave-based formulations and experimental data.

Main Methods:

• Development of a ray model based on geometrical acoustics.
• Incorporation of sound diffraction at barrier edges.
• Inclusion of multiple reflections from ground, barrier, and façade surfaces.
• Validation against a wave-based boundary element method.
• Comparison with scale model experimental studies.

Main Results:

• The developed ray model provides predictions for noise barrier insertion loss.
• The model effectively incorporates diffraction and multiple reflection effects, crucial for receivers near barriers.
• Good agreement was observed between the ray model and the boundary element formulation across a wide frequency range.
• Tolerable agreement was demonstrated between the ray model and scale model experimental data.

Conclusions:

• The ray model is a viable tool for predicting noise barrier insertion loss in urban environments.
• The inclusion of diffraction and multiple reflections is critical for accurate sound level predictions.
• The model shows good potential for application in urban noise barrier design and assessment.