Analysis of acoustic noise emissions from marine vessels

JASCO应用科学有限公司专门收集、分析和评估水下声学数据，用于**石油和天然气、海洋建筑、渔业和**国防部门的水下噪音环境影响评估。与加拿大交通部合作的一个具体项目是监测毗邻温哥华岛和**温哥华市的格鲁吉亚海峡海上交通产生的水下**声学噪音。通过对测量的声学数据进行协变量分析，结合自动识别**系统(AIS)的数据，如船舶类别、大小和通过船只的速度，JASCO正在构建一个预测的**海洋船舶噪声模型，该模型可能会影响法规以减少海洋交通噪声对环境的影响。**一个重要的问题是，与给定的**一组船舶特性相关的测量声级的高度可变性。据信，这种可变性源于**发动机噪声、轴和螺旋桨噪声以及船体和螺旋桨周围流动的空化(S)的综合可变性，所有这些**都可以独立于当前模型中考虑的参数而变化。在这些潜在的噪声源中，空化被认为是船舶噪声源的主要来源，也是最近许多船舶噪声研究的焦点。这种**特性将使该公司能够确定空化噪声如何影响记录的声学**频谱，从而改进噪声发射模型。这一增强的知识将提高**公司对海上交通进行环境影响评估的能力，这也可能对确定最佳船舶设计和运营制度产生**重大影响。

JASCO Applied Sciences Ltd. specializes in collecting, analyzing, and assessing underwater acoustic data for**environmental impact assessments of underwater noise for the oil and gas, marine construction, fisheries, and**defence sectors. A particular project, in collaboration with Transport Canada, has been to monitor underwater**acoustic noise due to marine traffic in the Strait of Georgia, adjacent to Vancouver Island and the city of**Vancouver. Through covariate analysis of measured acoustic data, in combination with automatic identification**system (AIS) data, such as vessel class, size, and speed of passing vessels, JASCO is constructing a predictive**marine vessel noise model that may influence regulation to reduce the environmental impact of marine traffic**noise.**One significant problem is a high degree of variability in the measured acoustic levels associated with a given**set of vessel characteristics. It is believed that this variability originates from a combination of variability in**engine noise, shaft and propeller noise, and cavitation of the flow around the vessel hull and propeller(s), all of**which can vary independently of the parameters currently considered in the model. Of these potential noise**sources, cavitation is believed to be the dominant source of noise source for marine vessels and has been the**focus of many recent studies of ship noise.**Identification of parameters that govern cavitation noise is of significant benefit to JASCO. This**characterization will enable the company to determine how cavitation noise influences the recorded acoustic**spectra, so that noise emission models can be improved. This enhanced knowledge will improve the**company's ability to perform environmental impact assessments of marine traffic, which could also have a**significant impact on determining optimal vessel designs and operating regimes.