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中文核心期刊

水下弹性球体对Bessel波束散射的计算及分析

Computation and analysis of the Bessel beam scattering by a submerged elastic sphere

  • 摘要: 以弹性球体为例,分析Bessel波束入射到水下物体时的声散射。将水下弹性球体声散射场的分波序列计算公式加以推广,应用于Bessel波束入射的情况。借鉴平面波散射的模式,通过几何分析指出了Bessel波束入射下镜反射波和Franz波干涉所形成的反向散射形函数上的峰一峰间隔与波束特征参数β的关系,并首次给出了峰峰间隔的预报公式。同时,采用共振散射理论对每阶分波的弹性散射单独分析,深入研究了β对纯弹性共振的影响,发现通过选取特定的β可以使相应阶分波的弹性散射贡献被消除,从而使在反向散射中对应频率及其附近处的共振得到显著的抑制。

     

    Abstract: Takeing an elastic sphere for example, the acoustic scattering of a submerged object illuminated by a Bessel beam is studied in this paper. The partial wave series representation for an elastic sphere has been extended to the case of Bessel beam scattering. Referring to the scattering of a plane wave, the peak to peak intervals in backscattering form function caused by the interference of the specular wave and the Franz wave have been analyzed in geometry. The influence of the characteristic parameter β of a Bessel beam on the peak to peak intervals has been indicated, and a predictive formula of the peak to peak intervals has been established for the first time. Meanwhile the elastic scattering of each partial wave has been separated based on the Resonance Scattering Theory (RST). The influence of β on the pure elastic resonance has been studied further. The results show that selecting specific β can reduce the contribution of a certain partial wave. Therefore the resonance at the corresponding frequency and the nearby region in the backscattering is remarkably suppressed. The work of this paper could be helpful to the applications of Bessel beams on the acoustic detection of submerged objects.

     

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