Solving an acoustic wave equation using a parabolic approximation is a popular approach for many available ocean acoustic models. Commonly used parabolic equation (PE) model programs, such as the range-dependent acoustic model (RAM), are discretized by the finite difference method (FDM). Considering the idea and theory of the "split-step" parabolic approximation, a discrete PE model using the Chebyshev spectral method (CSM) is derived, and the code is developed. We use the problems of two ideal fluid waveguides as examples, i.e., one with a constant sound speed in shallow water and one with a Munk sound speed profile in the deep ocean. The correctness of the discrete PE model using the CSM to solve a simple underwater acoustic propagation problem is verified. The test results show that compared with the finite difference discrete PE model, the proposed method in this paper has a higher accuracy in the calculation of underwater acoustic propagation in a simple marine environment and requires fewer discrete grid points. However, the proposed method has a longer running time than the finite difference discrete PE program. Thus, it is suitable to provide high-precision reference standards for the benchmark examples of the PE model.
翻译:使用抛物线近光线解决声波方程式是许多现有海洋声学模型的一种流行方法。通常使用的抛物线方程模型(PE)模型程序,例如以射线为主的声学模型(RAM),通过有限差分法(FDM)分离。考虑到“分步”抛物线近光线的理论和理论,将产生一个使用Chebyshev光谱法(CSM)的离散PE模型,并开发了代码。我们用两种理想流体波导导的问题作为例子,即浅水中保持恒定音速,深海中有一个沉积音速剖面模型。使用离散的PE模型解决简单的水下声学传播问题的正确性得到了验证。测试结果表明,与有限离散PE模型相比,本文件中的拟议方法在计算水下声学传播的精确度较高,需要更少的离心电网点。但是,拟议方法比离子光谱模型程序运行的参考时间更长。因此,它适合提供高精度标准。