Development of a low-frequency high-flow acoustic sensing array for turbulent ocean conditions

为了量化潮汐涡轮机安装对环境的潜在影响，有效的宽带 对海洋生物进行被动声学监测(PAM)以及 测量涡轮机和相关基础设施产生的噪声。然而，在潮汐航道，高 湍流会导致声学传感器表面产生伪噪声(流动噪声)，这是 尤其是在低频时，它掩盖了真实的声场。使用多个 同步水听器和阵列信号处理技术是解决这一问题的建议方案 挑战，允许不相关的伪噪声被抑制，而海洋哺乳动物产生的声音， 自然环境源和人为源可以被增强、分离和分类。 将在Fundy Ocean目前使用的潮汐涡轮机上设计和部署水平线阵列 能源研究中心(FORCE)网站。阵列在最小化流动噪声方面的有效性，同时 准确测量环境噪声、海洋哺乳动物声音和涡轮机产生的噪声将被评估。 收集的数据将与在单个自由漂流上收集的基准数据集进行比较 水听器使用抛物线方程和射线跟踪声学模型来考虑传播效应。这些 模型也将被用来评估涡轮机噪声监测在近场相对于 远场。性能参数作为数组元素数量、元素间距和流量的函数 速度将被量化。研究结果将验证和验证声学阵列的有效性 对于高速湍流会掩盖测量结果的环境中的长期PAM 带有伪噪声。

In order to quantify the potential environmental impacts of tidal turbine installations effective broadband acoustic sensing is required to perform passive acoustic monitoring (PAM) of marine life, as well as measurements of noise produced by the turbines and associated infrastructure. However, in tidal channels, high turbulent flow causes pseudo-noise (flow noise) to be generated on the surface of the acoustic sensors, which is especially problematic at lower frequencies where it masks the true sound field. The use of multiple synchronized hydrophones along with array signal processing techniques is a proposed solution to this challenge, allowing uncorrelated pseudo-noise to be suppressed while sounds generated by marine mammals, natural ambient sources, and anthropogenic sources may be enhanced, separated, and classified. A horizontal line array will be designed and deployed on a tidal turbine currently in use at the Fundy Ocean Research Center for Energy (FORCE) site. The effectiveness of the array in minimizing flow noise while accurately measuring ambient noise, marine mammal sounds, and turbine-generated noise will be evaluated. The collected data will be compared against a benchmark data set collected on a single free-drifting hydrophone using parabolic equation and ray tracing acoustic models to account for propagation effects. These models will also be used to evaluate the effectiveness of turbine noise monitoring in the near field versus the far field. Performance parameters as a function of the number of array elements, element spacing, and flow speeds will be quantified. The results of the study will verify and validate the effectiveness of acoustic arrays for long-term PAM in environments where high-speed turbulent flow would otherwise mask measurements with pseudo-noise.