Effect of Turbulence Scale Resolution on Numerical Simulation of Atmospheric Sound Propagation

摘要

The propagation of acoustic waves through spatially random, time-independent media has been extesively studied in recent years using a direct simulation approach. Currently, these simulations of a random field generated by a limited number of Fourier modes. In this paper the extension of the Random Fourier Modes (RFM) method to include simple time evolution and spatial inhomogeneoustatistics of the fluctuations is suggested. A "classical" parabolic equation is used for computing the acoustic field. We present results for propagation through an upward-refracting atmosphere. We examine the influence of inhomogeneities on propagation calculations. Further comparisons are made between cases that are identical save for the cutoff wavenumber of the turbulence spectrum used to derive the random index of refraction field.