楔形海域中三维效应对声源距离估计的影响分析*

楔形海域中声传播会出现显著的三维效应,导致水平方向上特定接收位置的声信号出现模态多次到达或者模态影区。利用射线模型,首先对楔形波导中的传播损失进行计算,分析三维效应的存在对于声波传播的影响, 结果表明,随着距离的增加,水平折射效应愈加明显,所得的三维结果与利用二维模型计算所得相差逐渐增大。然后对比二维声场和三维声场中的接收波形,并对其进行模态分离,证明在某些接收位置将会出现明显的模态多次到达或模态影区。最后通过匹配全波解以及分离出的各号简正波所对应的脉冲波形进行声源距离估计研究,并分析三维效应对于声源距离估计结果的影响。结果表明,由于三维效应的存在,使用三维模型能够得到准确估计声源距离,而利用二维模型进行估计得到的结果与实际距离相差较多,总体上偏大。

Analysis of source range estimation affected by three-dimensional effects in a wedge-shaped waveguide

The acoustic propagation will exist a significant three-dimensional effect in the wedge-shaped waveguide, and this effect can make the acoustic signal of horizontal direction appeared multiple mode arrivals or modal shadow zones in some specific receiving positions. Using the ray model, the transmission loss in the wedge waveguide is calculated firstly and the acoustic propagation affected by the existence of three-dimensional effect is analyzed. The result shows that the horizontal refraction effect becomes more obvious with the increase of the range, and the gap is gradually increased between the three-dimensional result and the calculated result by using the two-dimensional model. By comparing the received pulse waveforms in two-dimensional acoustic field and three-dimensional acoustic field, multiple mode arrivals or modal shadow zones in some receiving positions is subsequently confirmed. Finally, source range estimation is studied by matching the full wave solution as well as the separated normal modes, and the result of source range estimation affected by three-dimensional effect is analyzed. The result implies that applying the three-dimensional model can accurately estimate the source range, due to the existence of the three-dimensional effect, and the source range estimated by two-dimensional model greatly differs from the actual source range, which is larger on the whole.