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Development of wide-angle PE calculation method for long-range sound propagation in ocean current.

洋流中远距离声传播的广角PE计算方法的发展。

基本信息

批准号：
11650954
负责人：
ENDOH Nobuyuki
金额：
$ 2.18万
依托单位：
Kanagawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650954/
关键词：
PE Method Long-range Ocean current Precision FDTD Sparrow water

项目摘要

In order to develop an ocean acoustic tomography technique, it is very important to estimate the long-range propagation sound. Two precise computer simulation programs were developed for obtaining the sound propagation characteristics across ocean currents. We investigated the wide-angle Parabolic Equation (PE) method using Douglas operator scheme, which was very accurate. The accurate PE calculation method showed that it was applicable for calculation of sound propagation in deep ocean and shallow water. The result of ASA benchmark problem solved by PE method agreed well with other method. We also developed the Finite Difference Time Domain (FDTD) method for calculating the propagation sound in shallow water with lossy seabed. The FDTD method, which is taking account of attenuation of a lossy seabed, solved the test problem discussed in the PE II Workshop. It calculated a contour map of the sound pressure when the continuous wave was projected. The transmission loss pattern as a function of range is also calculated. Its results agreed well with the results of a coupled-mode calculation not only in water but also in seabed. The FDTD method is also capable of visualizing the propagated pulse waveforms in the same model. It showed that the incoming pulse has returned from the top of the convex seabed. It was also shown the interference wave between direct wave and reflected waves. These results show the validity of the FDTD method.

为了发展海洋声层析成像技术，对远距离传播声的估计是非常重要的。为了获得声在海流中的传播特性，开发了两个精确的计算机模拟程序。研究了高精度的道格拉斯算子格式下的宽角抛物方程方法。结果表明，该方法适用于深海和浅海声传播的计算。用PE方法求解阿萨基准问题的结果与其它方法吻合较好。我们还发展了时域有限差分法（FDTD）计算浅海中的传播声与有耗海底。FDTD方法，这是考虑到有耗海底的衰减，解决了在PE II研讨会上讨论的测试问题。当连续波被投射时，它计算了声压的等值线图。还计算了作为范围的函数的传输损耗模式。其结果不仅与水中的耦合模计算结果一致，而且与海底的耦合模计算结果一致。时域有限差分法还能够在同一模型中可视化传播的脉冲波形。这表明入射脉冲是从凸起的海底顶部返回的。同时也揭示了直达波和反射波之间的干涉波。这些结果表明了FDTD方法的有效性。