Javier Rodrigo F, Jaime Ramis, Pedro Poveda, Jesus Carbajo, Enrique Segovia
Department of Physics, Systems Engineering and Signal Theory, University of Alicante, Ctra. San Vicente del Raspeig, 03080 Alicante, Spain.
Department of Civil Engineering, University of Alicante, Ctra. San Vicente del Raspeig, 03080 Alicante, Spain.
Sensors (Basel). 2023 Jan 16;23(2):1035. doi: 10.3390/s23021035.
Shipping traffic is recognised as the main man-noise source of the anthropogenic noise generated in the marine environment. The underwater acoustic pollution is increased due to the increment of the human activity at seas supposing a threat for marine habitats. The ship as acoustic source must be understood and controlled to manage the maritime areas both in time and space to reduce the impact of noise in marine fauna. Shipping noise is mainly composed of flow noise, propeller noise and machinery noise. This research is focused on the analysis and estimation of the underwater radiated noise generated by the vibrations of the onboard machinery or structure-borne noise based on the calculation of the transfer function. This function relates the acceleration levels of the vibrations of the hull's panels and the radiated noise by them using the radiation efficiency. Different analytical methods to estimate the radiation efficiency are presented and compared with data collected at sea. The measurements are performed acquiring simultaneously acceleration and acoustic levels by means on accelerometers installed on the hull's panels at different positions and hydrophones deployed close to the bow, middle and stern of the ship. The analysis of the transmission of the vibrations along the ships is performed using the data from different locations of the hydrophones. The quality of the measurements is analysed using the coherence function through the spectral correlation between the measurement of vibrations and acoustic levels. On the other hand, signal-to-noise ratio is computed to verify the strength of the noise sources. The computed transfer function is used to predict the underwater radiated noise from vibrations showing differences less than 2 dB re to 1 μPa.
航运交通被认为是海洋环境中人为产生的主要人为噪声源。由于海洋上人类活动的增加，水下声污染加剧，这对海洋栖息地构成了威胁。必须了解并控制作为声源的船舶，以便在时间和空间上管理海域，减少噪声对海洋动物的影响。航运噪声主要由水流噪声、螺旋桨噪声和机械噪声组成。本研究的重点是基于传递函数的计算，分析和估计船上机械振动或结构噪声产生的水下辐射噪声。该函数利用辐射效率将船体板振动的加速度水平与它们产生的辐射噪声联系起来。提出了不同的估计辐射效率的分析方法，并与海上收集的数据进行了比较。测量是通过安装在船体不同位置的加速度计和部署在船首、船中及船尾附近的水听器同时获取加速度和声级来进行的。利用来自水听器不同位置的数据对沿船舶的振动传递进行分析。通过振动测量和声级之间的频谱相关性，利用相干函数分析测量的质量。另一方面，计算信噪比以验证噪声源的强度。计算得到的传递函数用于预测振动产生的水下辐射噪声，其显示的差异小于相对于1μPa为2dB。
