舰船做为体积声源的源强度谱纵向分布特性

在近程声探测条件下，舰船应被视为体积声源，而非点声源。建议用舰船的噪声源强度谱纵向分布特性描述舰船辐射噪声能量沿舰船纵向及频域的二维分布，探讨船船不同部位辐射噪声的源强度和功率谱特征，籍助对舰船噪声通过对特性信号的时频分析，得到了若干典型舰船的噪声源强度谱纵向分布特性，结果证明，在正常巡航速度时，沿舰船首尾方向分布着三个具有明显功率谱特点的声辐射部位，即推进器部位一，主机部位和辅机部位，这个结论称为正常巡航速度时舰船噪声的“三亮点”模型，简明讨论了在低航速和很高航速时舰船噪声源强度谱纵向分布特性的变化。

The Longitudinal Distribution of Source Intensity Spectrum of Ship-radiated noise

For passive acoustic detection at short distance, a ship should be considered to be a volume sound source, not a dot one. This paper is intended to propose a new concept, the longitudinal distribution of source intensity spectrum of ship radiated noise, to exhibit the spatial and spectral distributions of the noise energy and the diverse sound signature at some special sections of ships. The longitudinal distributions of source intensity spectrum of several typical ships is given on the basis of time frequency analysis of the passage signature of ship radiated noises. The results indicate that at cruise speed and along the fore and aft direction of the ships there are three positions, propeller, main engine and donkey engine, which radiate noise signature with remarkable energy and power spectrum features. This conclusion is named three highlight model of ship radiated noise at cruise speed. The paper also discusses the longitudinal distributions of source intensity spectrum of ship radiated noise at low speed and very high speed.