Impact of multiple reflections on urban acoustics

Abstract

Understanding how the urban form contributes to noise is important for the successful acoustic design of cities. The amplification of sound is mainly due to the multiple reflections that occur between the high and parallel walls of urban canyons. This study explores the use of ray tracing at the urban scale through the measurement and simulation of three configurations. These are referred to as “1D”, “2D” and “3D”. Impulse response measurements performed at points located on the top of the façades show an increase of 6 dB for the “2D” case and 11 dB for the “3D” case. These results are consistent with ray tracing simulations. This kind of simulation is useful to determine the influence of the street aspect ratio on the sound level. Since specular reflections are related to geometry, a spatialized representation is proposed and discussed.

Seeking the Nexus Between Building Acoustics and Urban Form: A Systematic Review

“…The vertical noise mapping prediction showed 2.2 dBA lower than the actual noise sampling, and therefore the study concludes that this method might be useful for measuring the noise effect of facades on high-rise buildings. Finally, De Bort and Beckers [38] assessed the noise effects on walls by using the ray tracing method for three scenarios.…”