Abstract:

Recent advances in the numerical techniques and physical models used in sound propagation codes for the atmosphere have greatly improved the correspondence between calculated and measured fields. In particular, incorporating models of atmospheric turbulence have provided major advances. In this paper, an approach to turbulence modeling is described which the authors have developed in the last few years. The turbulence is represented as a superposition of a limited number of random Fourier modes and the acoustic waves are propagated through each individual realization of this field using a wide angle parabolic equation. Statistical results are obtained through ensemble averaging. Illustrations will be given for both line of sight propagation and for propagation into a refractive shadow zone. The influence of the physical model (vectorial versus scalar and Gaussian versus inertial) on the predicted sound field will be discussed. Extensions to time-domain analyses will also be considered.