Salomons E M
TNO Institute of Applied Physics, Delft, The Netherlands.
J Acoust Soc Am. 2000 Oct;108(4):1528-34. doi: 10.1121/1.1289670.
The validity of the axisymmetric parabolic-equation (PE) method for line-of-sight sound propagation in a turbulent atmosphere is investigated. The axisymmetric PE method is a finite-difference method for solving a 2D parabolic wave equation, which follows from the 3D wave equation by the assumption of axial symmetry around the vertical axis through the source. It is found that this axisymmetric approximation has a considerable spurious effect on the fluctuations of the sound field. This is concluded from analytical expressions for the log-amplitude and phase variances, derived both for isotropic turbulence and for axisymmetric turbulence. The expressions for axisymmetric turbulence are compared with the results of numerical computations with the PE method.
研究了轴对称抛物方程（PE）方法在湍流大气中视线声传播的有效性。轴对称PE方法是一种求解二维抛物波动方程的有限差分方法，它是通过假设围绕穿过声源的垂直轴的轴对称性，从三维波动方程推导出来的。结果发现，这种轴对称近似对声场的波动有相当大的虚假影响。这是根据针对各向同性湍流和轴对称湍流推导的对数幅度和相位方差的解析表达式得出的结论。将轴对称湍流的表达式与用PE方法进行数值计算的结果进行了比较。
