海冰声波导斜入射波场快速预报方法
Rapid prediction of oblique incident wave field in sea ice acoustic waveguide
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摘要: 为提高海冰中声波传播特性的计算效率, 提出了一种针对冰下声信源指向性激发的半解析解冰声导波波场预报方法。首先, 利用一维有限元算法对水中声源激励下的冰中应变场进行时域推演, 并考虑流固耦合界面上的声能量转换效应。随后, 结合海冰声波导泄漏模态的频散特性, 以解析方式推导不同传播距离与深度处的模态弹性导波位移时程, 实现海冰中波场的快速预报。与其他数值方法的对比结果表明, 该方法在低频、相同模型条件下的计算速度提升了3个数量级, 在保证计算精度的同时显著降低了计算时间和存储需求。相比传统有限元方法, 该方法有效克服了计算成本随传播参数(如水平距离和工作频率)增加而快速增长的限制, 特别适用于高频和远距离传播条件下的计算需求。Abstract: This paper proposes a semi-analytical ice acoustic guided wave field prediction method for the directional excitation of sub-ice acoustic sources. The one-dimensional finite element algorithm is used to realize the time-domain deduction of the strain field in ice from the excitation of underwater acoustic sources, taking into account the acoustic energy conversion at the fluid-solid coupling interface. The acoustic waveguide leakage modal dispersion curve of the sea ice is then used to derive the excitation analytically. A rapid prediction of the wave field in sea ice is completed according to the displacement time course of the modal elastic guided wave propagation at a given distance and depth. Comparison with other numerical methods shows a significant improvement in computational speed of three orders of magnitude for the same model conditions at low frequencies, significantly reducing computational time and storage requirements while maintaining computational accuracy. Compared to traditional finite element methods, this method effectively overcomes the limitation that the computational cost increases rapidly with increasing propagation parameters (e.g. horizontal distance and operating frequency), and is particularly suitable for high-frequency and long-distance propagation conditions.