Over the past several decades, a large number of numerical models have been developed for underwater acoustic propagation. Most of these models provide solutions for two-dimensional (2D) problems, and they provide satisfactory solutions for the majority of propagation problems where the environmental dependence on azimuth is insignicant.

However, acoustic propagation and scattering in the ocean usually involves fully three-dimensional (3D) effects. The full solution of general 3D propagation and scattering is very intensive computationally. Various 3D methods have been developed, and some of those can provide approximate solutions for 3D problems.

Recently, a coupled-mode method with the use of the direct global matrix (DGM) approach was proposed by researchers from the Institute of Acoustics, Chinese Academy of Sciences (IACAS), hereafter referred to as the DGMCM model. This method is capable of handling 2D problems with either a point source in cylindrical geometry or a line source in plane geometry. The DGMCM model can accurately and efficiently model propagation and scattering in very complicated waveguides, but it is restricted to 2D problems.

As a result, another group of researchers from IACAS extend the DGMCM model to 3D acoustic propagation and scattering in 2D waveguides. This method synthesizes the 3D field solution by using Fourier transform techniques. And the techniques are based on a sequence of 2D problems, each of which is solved by a numerical model developed by DGMCM.

Numerical results indicate that the present model is remarkably accurate, and thus it can serve as benchmark against other numerical models. In addition, this model can be applied to realistic problems. Moreover, it can also be used to analyze horizontal refraction in some range-dependent waveguides in reality, such as the continental shelf environment, ridge-like bathymetry, and underwater trench.

This research is supported by the National Natural Science Foundation of China under Grant Nos 11125420 and 11174312, and the Knowledge Innovation Project of the Chinese Academy of Sciences.

The research entitled "Three-Dimensional Sound Propagation and Scattering in Two-Dimensional Waveguides" has been released in CHIN. PHYS. LETT. (Vol. 30, No. 11, July 2013).

Correspondence author:

QIN Jixing

State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190

Email: qjx@mail.ioa.ac.cn