Computing acoustic transmission loss using 3D Gaussian ray bundles in geodetic coordinates
Date of Original Version
This paper defines a new three-dimensional (3D) Gaussian ray bundling model in geodetic coordinates: latitude, longitude, and altitude. Derivations are provided for 3D refraction, 3D interface reflection, 3D eigenray detection, and a 3D variant of the Comprehensive Acoustic System Simulation (CASS)/Gaussian Ray Bundling (GRAB) model. This approach allows environmental parameters and their derivatives are computed directly in latitude, longitude, and depth directions without reducing the problem to a series of N ×2D Cartesian projections. Our model supports 3D effects such as great circle routes and horizontal refraction in sloped environments. Key test results are included for ray path refraction accuracy using a Munk profile, Gaussian beam projection into the shadow zone for an n2 linear profile, and horizontal refraction from a 3D analytic wedge. Testing to date indicates that this approach has accuracy at least as good as CASS/GRAB, but with improved execution speed benefits for large numbers of targets, and 3D transmission loss effects.
Journal of Computational Acoustics
Reilly, Sean M., Gopu R. Potty, and Michael Goodrich. "Computing acoustic transmission loss using 3D Gaussian ray bundles in geodetic coordinates." Journal of Computational Acoustics 24, 1 (2016). doi:10.1142/S0218396X16500077.