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涡旋是深海环境中频繁出现的海洋现象, 它会引起上层海水的声速扰动, 改变海面风成噪声的传播过程, 最终导致噪声场特性异常. 本文采用高斯涡模型描述涡旋引起的声速扰动, 分别使用射线和抛物方程模型描述近场和远场噪声信号的传播, 研究了涡旋对其水平中心位置不同深度上的风成噪声垂直空间特性(包括噪声垂直方向性和垂直相关性)的影响. 研究表明: 1)在涡心深度上, 涡旋对噪声垂直空间特性的影响最大, 其中冷涡导致噪声垂直方向性中水平凹槽的宽度增加, 凹槽下边缘峰值的高度降低, 噪声垂直相关性减弱, 暖涡的影响反之; 2)在远离涡心的深度上, 涡旋对噪声垂直空间特性的影响减小, 冷涡和暖涡分别仅引起噪声垂直方向性中水平凹槽下边缘峰值的高度升高和降低, 对噪声垂直相关性几乎没有影响; 3)涡旋对噪声垂直空间特性的影响均随其绝对强度增大而增强. 针对以上现象, 使用射线逆推方法分析了涡旋影响噪声垂直空间特性的机理. 该方法由噪声接收点发射声线, 利用声场互易性分析噪声沿声线反向到达接收点的俯仰角和能量大小. 分析表明, 存在涡旋时, 噪声沿海面反射声线反向到达接收点的俯仰角和能量变化, 是引起噪声垂直空间特性变化的主要原因. 此外, 仿真表明, 当接收点偏离涡旋水平中心但两者距离较近时, 研究中的分析和结论仍是近似成立的.Mesoscale eddy is a marine phenomenon occurring frequently in deep ocean, and it will disturb the sound speed in the upper water layer. As a result, the mesoscale eddies will influence the propagation of wing-generated noise and cause the noise field to vary. In this paper, we investigate the effects of mesoscale eddies on the vertical spatial characteristics (including the noise vertical directionality and the noise vertical correlation) of wind-generated noise at different depths of its horizontal center of the eddy. In the study, the Gaussian eddy model is used to describe the sound speed fluctuation, and the ray and parabolic equation theories are used to describe the noise propagating in the near field and far field, respectively. Simulations indicate as follows. 1) At the depth of the eddy center, a clod-core eddy causes both the width of the horizontal notch and the noise vertical correlation to decrease, while the effect of a warm-core eddy is contrary to that of the cold-core eddy. 2) At the depth far from the eddy center, the effect of eddies is reduced, a cold-core and a warm-core eddy only lead the peak at the down edge of the horizontal notch in the noise directionality to rise and fall, respectively, and do not influence the noise vertical correlation. 3) The effect of an eddy becomes severe as its absolute strength becomes higher. The ray reversion method based on the principle of reciprocity is used to explain the physical reason behind the above phenomena. By the method the rays are launched from the noise receiving point and the polar angle and the strength of the noise arriving reversely along the ray paths are analyzed. It is shown that the change of the polar angle and the strength of the noise arriving reversely along the surface reflected ray paths in the presence of eddies are the main cause for changing the noise vertical spatial characteristics. Furthermore, simulations show that the analyses and conclusions in the study are still approximately valid when the receiving point deviates from the eddy center but the horizontal distance between them is short.
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Keywords:
- eddy/
- wind-generated noise/
- vertical directionality/
- vertical correlation/
- ray model/
- parabolic equation model
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$ D_{\rm c} $ $\theta_{{\rm{SR} }, {\rm{min} }}$ $\theta_{{\rm{SR} }, {\rm{max} }}$ $\theta_{{\rm{SR} }, {\rm{c} }}$ $ \Delta \theta_{\rm{SR}} $ 0 104.3° 105.1° 104.70° 0.8° –40 109.3° 110.0° 109.65° 0.7° 40 96.3° 97.7° 97.00° 1.4° 
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$ D_{\rm c} $ $\theta_{{\rm{SR} }, {\rm{min} }}$ $\theta_{{\rm{SR} }, {\rm{max} }}$ $\theta_{{\rm{SR} }, {\rm{c} }}$ $ \Delta \theta_{\rm{SR}} $ 0 102.3° 103.4° 102.85° 1.1° –40 102.0° 103.4° 102.70° 1.4° 40 102.7° 103.4° 103.05° 0.7° 下载:
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