Abstract To determine the radiated sound power of an underwater sound source below the first resonance frequency in a non-anechoic tank, a sound intensity measurement technique based on separating near-field acoustic energy flux is proposed. A theoretical analysis of vibration and acoustic radiation of underwater structures shows that the variation in the radiation impedance of the sound source in the given frequency band is much smaller than the mechanical impedance, and the vibration state of the sound source changes negligibly compared with that of the sound source in the free field. This theoretical analysis is verified experimentally. Based on this analysis, the acoustic energy flux is determined at various locations on the enveloping surface by first measuring the near-field sound pressure and the normal component of the particle velocity on the surface. The efflux and influx sound energies at an enveloping surface are separated to obtain the free-field radiated sound power of the source to be tested. This approach is tested by measuring the low-frequency radiated sound power of an underwater transducer source in a glass tank. The test results show that the maximum difference between the sound power measured in the glass tank and that measured in the anechoic tank is less than 0.8 dB.

中文翻译：

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基于近场声能通量分离的非消声水池低频声功率测量技术

摘要 为确定非消声水池中低于一阶共振频率的水下声源的辐射声功率，提出了一种基于分离近场声能通量的声强测量技术。水下结构振动与声辐射的理论分析表明，给定频带内声源辐射阻抗的变化远小于机械阻抗，声源的振动状态与机械阻抗相比变化可忽略不计。自由场中的声源。这种理论分析得到了实验验证。基于这一分析，通过首先测量近场声压和表面上粒子速度的法向分量，确定包络表面不同位置的声能通量。将包络面处的流出和流入声能分开，以获得待测源的自由场辐射声功率。这种方法是通过测量玻璃罐中水下换能器源的低频辐射声功率来测试的。测试结果表明，在玻璃罐中测得的声功率与在消声罐中测得的最大声功率差小于0.8 dB。这种方法是通过测量玻璃罐中水下换能器源的低频辐射声功率来测试的。测试结果表明，在玻璃罐中测得的声功率与在消声罐中测得的最大声功率差小于0.8 dB。这种方法是通过测量玻璃罐中水下换能器源的低频辐射声功率来测试的。测试结果表明，在玻璃罐中测得的声功率与在消声罐中测得的最大声功率差小于0.8 dB。