浅海运动目标辐射声测量距离内声聚焦特性研究

Shallow water acoustic focusing of noise radiated from moving targets within measuring distance

随着影响目标辐射噪声测量诸多因素的解决,声聚焦对测量精度的影响已显得比较突出.研究了浅海近场声聚焦特性对目标辐射噪声测量结果的影响.在射线理论基础上,推导了声压场和质点振速场的数学表达式,建立了基于虚源法的浅海矢量声场计算模型,并将声场计算模型应用于宽带声源信号矢量声场计算中.比较分析了理论仿真计算和湖试结果,验证了浅海近距离矢量声场计算模型的正确性,进一步探讨了浅海声场聚焦特性以及如何减小声聚焦对目标辐射噪声测量的影响.

Deviations are induced in near field radiated noise measurements in shallow water due to obvious phenomenon of acoustic focusing. How to eliminate the influence of acoustic focusing on measurements, and ways to improve the accuracy of the measurement results have been a significant concern of researchers. In this paper, the mathematical expressions of the sound pressure field and particle velocity field were deduced based on Ray Theory. Then a calculating model of the vector acoustic field in shallow water, which was based on the image source method, was established and applied to the calculations when sound sources were broadband signals. Through comparison and analysis of simulations and lake testing results, this model was proven to be correct. Further exploration was conducted on the characteristics of acoustic focusing in shallow water and methods for reducing their influence on radiated noise measurements.