一种基于波数积分方法的线源声场计算方法

A wavenumber-integration method based solution to the acoustic field excited by a line source

提出了在Pekeris波导条件下,一种基于波数积分方法的线源声场中的稳定数值计算方法。通过对深度格林函数中上行波与下行波的归一化,得到稳定的系数矩阵,从而求得格林函数的解析解。对深度格林函数进行模式展开,验证了该方法得到的深度格林函数解析解的准确性。结合仿真实例,将该方法得到的波数积分模型与传统简正波模型KRAKENC的结果进行比较,结果显示,当某号简正波的波数与海底波数接近时,KRAKENC计算不出该号简正波,会导致KARKENC的计算结果不准确,而波数积分方法可以很好地解决该问题。因此,提出的方法可以作为Pekeris波导中线源激发声场的标准模型。

An unconditionally stable computation method based on the wavenumber integration method is presented for the acoustics field excited by a line source in a Pekeris waveguide. Both up and down going waves in the depthdependent wave equation are appropriately normalized in order to obtain a stable coefficient matrix. Analytical solution to the depthdependent Green＇s function is also presented. Modal expansion of the Green＇s function is performed to validate the analytical solution. It indicates that the analytical solution is accurate. The transmission loss calculated by this method is compared with those given by KRAKENC with an example. It shows that when a certain mode is close to the bottom wavenumber, KRAKENC fails to find this mode. As a result, the field result by KRAKENC is inaccurate. However, the wavenumberintegration method suits well for such problems. Numerical results indicate that the present model can serve as a benchmark model for the problem of sound propagation excited by a line source in a Pekeris waveguide.