低频水声通信系统水听器流噪声数值分析

Numerical Analysis of Flow Noise Around Hydrophone Over Low-frequency Underwater Acoustic Communications

低频水声通信是实现远距离水下无线通信的一种重要方式,在海洋科考、环境监测及军事等领域应用广泛。流噪声是制约低频水声通信传输距离的重要因素之一。不同于以往对充油的拖曳线列阵声呐的流噪声研究,由于低频水声通信系统常用换能器和裸露水听器实现水下信号的发送和接收,本文以该系统中裸露水听器流噪声为研究对象,采用大涡模拟方法( Large Eddy Simulation, LES )和声学类比方法对水听器周围的流场、声场进行数值模拟计算分析,研究在不同外形参数、运动参数下的水听器周围的流噪声。分析对比结果表明裸露水听器周围的流噪声对低频水声通信存在影响,且流噪声声压级随着运动速度的增加而提高。本研究为提升远程低频水声通信性能提供了噪声方面的理论基础。

The low-frequency underwater acoustic communications are one of the significant means to realize the long-distance underwater wireless communications. Extensive applications have reached to oceanographic survey and research, environmental monitoring, military services, et al. However, flow noise has severely restricted the transmission distance of low-frequency underwater acoustic communications. Although the flow noise in towed array has been investigated sufficiently, since the low-frequency underwater acoustic communication system transmits and receives signals with transducer and bare hydrophone respectively, this paper studies the flow noise of the bare hydrophone under different shapes and motion parameters. It uses large eddy simulation to simulate and analyze the hydrophone ’ s flow field and acoustic analogy method to calculate its sound field. The results show that the influence of flow noise over low-frequency underwater acoustic communications cannot be ignored and its sound pressure level increases along with the increasing moving speed. This study lays the theoretic basis in terms of noise for the improvement of low-frequency underwater acoustic communications performance.