Accuracy and efficiency analysis of a road traffic noise propagation calculation method based on beam tracing

Abstract

The development and implementation of a traffic noise propagation calculation method based on beam tracing subordinated to spatial subdivision is presented to simulate noise attenuation in three-dimensional space. In the method, complex scenes constituted by road, different buildings and thin sound barrier and all noise propagation modes including direct, reflected, diffracted and composite are considered. The paper analyses the accuracy and efficiency of the method from the perspectives of subdivision precise of obstacles and road, beam thresholds and re-subdivision of sound barrier areas. The results presented by tendencies chart and formulas indicate that a meticulous subdivision and threshold settings lead to more accurate but less efficient method. Results of experiment and case study show the error to be no more than 0.3 dB when the building subdivision precisions (0.5 m), road subdivision precision (2 m) and thresholds (a length threshold of 500 m, three reflections and one diffraction) are set appropriately. Re-subdivision of sound barriers is presented to handle the trade-off between accuracy and efficiency caused by discrepancies in the geometric dimensions. In the case study, re-subdivision mitigates the trade-off between accuracy and efficiency, with almost the same accuracy by spending only approximately 1/10 of the time. A building subdivision precision of 1 m, a road subdivision precision of 2 m, a 500 m beam length, 3-5 reflections and a single diffraction are recommended for the method.

Simulation and Analysis of Road Traffic Noise among Urban Buildings Using Spatial Subdivision-Based Beam Tracing Method

“…The empirical methods such as ISO model [23] and its developing model [24,25], taking building density and the effects of front buildings into consideration, resulting in relatively large errors. Validated with reasonable accuracy and efficiency [26,27], the geometric acoustic method has been applied in traffic noise simulation, which consists of beam tracing method (BTM) [28,29], ray tracing method (RTM) [30,31] and image source method (ISM) [32]. With the assumption of sound waves are non-flexural, these methods are suitable in traffic noise simulation in urban building area as the wavelengths of traffic noise are much smaller than the building dimensions usually.…”

“…Hence, BTM is widely used in noise simulation outdoors. For example, Wang et al [26,33] and Luo et al [34] presented beam tracing methods for traffic noise simulation. Considering the complex urban buildings environment, these studies avoid high computational complexity by pretreating the space.…”

Fault diagnosis of bearing based on the kernel principal component analysis and optimized k-nearest neighbour model

“…The specific explanation for this can be found in literature. [14][15][16] The nature of LMD is to demodulate the AM-FM signals. By using the LMD method, a complicated signal can be decomposed into a set of PFs, each of which is the product of an envelope signal and a pure FM signal.…”

Investigation of vibration induced by moving cranes in high-tech factories

“…Arnaud et al 27 reviewed the improvement of the quality of buildings regarding sound insulation and reducing noise exposure, and this review presented a state-of-the-art of annoyance due to a combined exposure to vibrations and noise. Wang et al 28 developed a traffic noise propagation calculation method to simulate noise attenuation, and results of experiment and case study showed the error to be no more than 0.3 dB when the building data were appropriately set.…”