Ostashev Vladimir E, Breton Daniel J, Wilson D Keith
U.S. Army Engineer Research and Development Center, Hanover, New Hampshire 03755, USA.
J Acoust Soc Am. 2024 Jul 1;156(1):107-118. doi: 10.1121/10.0026452.
The interference of the direct and ground-reflected sound waves is significantly affected by volumetric scattering in the atmosphere, such as scattering by turbulence and forest. In the present article, the existing theory describing this interference is generalized to three somewhat independent but equally important cases. First, the attenuation of the direct and ground-reflected waves caused by backscattering is addressed. Second, the existing theory is extended for statistically quasi-homogeneous turbulence in which the variances and length scales of the temperature and wind velocity fluctuations depend on the height above the ground. Third, the existing theory, which was previously formulated only for near-horizontal sound propagation, is generalized to slanted sound propagation as pertinent to elevated sound sources. Numerical results for slanted propagation demonstrate that atmospheric turbulence can significantly increase the sound pressure level at the interference minima. The extended theory of the interference of the direct and ground-reflected waves in the atmosphere with volumetric scattering is important for practical applications, such as auralization of flying aircraft and sound propagation in a forest, and can be adapted to radio wave propagation.
直达声波与地面反射声波的干涉会受到大气中体散射的显著影响，例如湍流和森林引起的散射。在本文中，描述这种干涉的现有理论被推广到三个在一定程度上相互独立但同样重要的情况。首先，讨论了后向散射引起的直达波和地面反射波的衰减。其次，将现有理论扩展到统计上准均匀的湍流，其中温度和风速波动的方差和长度尺度取决于离地面的高度。第三，现有的理论以前仅针对近水平声传播制定，现在推广到与高架声源相关的倾斜声传播。倾斜传播的数值结果表明，大气湍流可显著提高干涉极小值处的声压级。考虑体散射的大气中直达波与地面反射波干涉扩展理论对于实际应用很重要，例如飞行飞机的听觉化和森林中的声音传播，并且可适用于无线电波传播。
