AN IMPROVED GAUSSIAN BEAM TRACING METHOD FOR THE LONG-DISTANCE SOUND WAVE PROPAGATION IN NONUNIFORM MEAN FLOWS

This paper presents an improved Gaussian beam tracing (GBT) method to efficiently compute the long-distance sound wave propagation in non-uniform mean flows. In the ray acoustics framework, the dynamic ray tracing (DRT) equations are derived from the convected wave equation. The high-frequency asymptotic paraxial solution of the acoustic potential and the corresponding Gaussian beam are developed along the ray based on the DRT equations. Through a revised weighting function that considers the convection effect, the sound pressure field can be accurately computed by integrating each vicinal beam’s contribution at the receiver. This GBT method is valid at caustics, removing the singular results of the standard ray method, and it also provides smooth transitions of sound field intensities at shadow zone boundaries. The sound wave propagation in an inhomogeneous stratified flow is studied using the proposed GBT method, and the result agrees well with the numerical solution based on solving the linearized Euler equations using the finite element method. Therefore, this work establishes the generalised extension of the GBT method in the quiescent medium to the medium with inhomogeneous flows and provides an effective way to model the high-frequency sound wave propagation in large-scale complex environments.