Numerical Simulation on Acoustic Scattering Characteristics of Targets Buried in Fluctuating Seabed
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摘要: 基于COMSOL多物理场平台下的有限元数值计算方法, 完成收发分置条件下掩埋弹性目标声散射数值计算。运用高斯谱法建立起伏海底模型, 给出粗糙海底起伏高度、相关长度、掠射角等参数对掩埋目标声场特性的影响。结果表明, 在单一方向入射多点线阵上接收, 计算得到收发分置的信混比呈现起伏特性: 平坦或小起伏海底前向波形振荡剧烈且呈现准周期性, 随着海底粗糙程度增加, 起伏的规律性逐渐消失。当声波垂直照射海底时, 海底起伏的相关长度变化对散射能量瑞利方差影响较大, 而几乎不改变瑞利均值。斜入射时, 相关长度和起伏高度均是影响瑞利方差和均值的主要因素。研究成果为海底掩埋目标声探测提供了参考依据。Abstract: The acoustic scattering of buried elastic target under the bistatic condition is numerically calculated with the finite element method(FEM) on the COMSOL multi-physical field platform. A fluctuating seabed model is established by Gaussian spectrum method, and then the effects of fluctuation height, correlation length, grazing angle and other parameters on the acoustic characteristic of buried targets are obtained. The results show that the echo-to-reverberation ratio of the bistatic is fluctuant when sound enters in single direction while is received on a multi-point linear array. That is, for flat or gently fluctuating seabed, the forward waveform oscillates violently and presents quasi-periodicity, but the regularity of the echo-to-reverberation ratio fluctuation gradually disappears with the increase of seabed roughness. When a sound wave irradiates the seabed vertically, the variation of the correlation length of seabed fluctuation has a significant influence on the Rayleigh variance of the scattering energy, but has little effect on Rayleigh mean. If a sound wave enters obliquely, the correlation length and fluctuation height are the main factors affecting the Rayleigh variance and mean value. These results may provide a reference for acoustic detection of buried targets in seabed.
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Key words:
- fluctuating seabed /
- ried target /
- acoustic scattering /
- bistatic
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