Efficient computation of broadband noise propagation using Gaussian beam tracing method

Abstract

The Gaussian beam tracing method has advantages in computing long-distance noise propagation in outdoor environments due to its high efficiency. Usually, repeated computations are required if the target sound wave is broadband or contains multiple frequencies because the method was developed in the frequency domain. This paper presents an efficient computation of broadband noise propagation using Gaussian beam tracing. The approach is based on the fact that the ray behaviors and source properties can be decoupled at high frequencies, where the wave equation is asymptotically solved. Consequently, only a single computation is needed to determine the frequency-independent ray properties, including ray-centered coordinates and beam dynamics. Then sound waves at different frequencies can be simultaneously introduced in a single computation. By separating the processes of determining the ray properties and incorporating the broadband noise source in the numerical implementation, the computational cost can be largely saved. In this work, several benchmark problems are studied, showing that the efficiency could be increased in comparison to the multiple individual computations. A computation acceleration up to 35-fold could be achieved when 200 frequency components are applied. The method is also applied to study the impact of broadband noise due to multiple drone propellers in urban environments. Applications to stochastic broadband problems are also discussed.

Efficient prediction of airborne noise propagation in a non-turbulent urban environment using Gaussian beam tracing method

“…Nevertheless, in the presence of strong refraction due to wind velocity variations, the GBT prediction deviated up to 10 dB from the experimentally measured results. Recently, several GBT tools (Bian et al, 2020(Bian et al, , 2021Bian et al, 2022;Mo et al, 2017) have been developed and applied to atmospheric acoustic propagation problems. Although these tools are efficient in RPT, they cannot account for atmospheric refraction due to horizontal or vertical variability in the wind velocity in a three-dimensional (3D) environment.…”