船舶尾流气泡幕电磁特性研究

发布时间：2018-08-06 16:17

【摘要】：船舶在海面上运动时,会在运动方向的反方向产生一条尾迹,即船舶尾流。该尾流产生的原因是船体和螺旋桨对海水的扰动,形成一条具有多种物理性质的气泡幕带。受天气、气温、水温、海域、航速等因素影响,尾流具有不同的物理特性和外貌特征,研究这些特性和特征,可以映射出船舶本身的类型、吨位、航速等信息,对军事、海洋观测等领域具有极大的意义。本文研究的内容为船舶尾流气泡幕的电磁性质,主要包括以下几个方面：第一,利用自行研制的实验装置,模拟尾流气泡幕的生成,在此基础上分别对静止水面、单螺旋桨尾流和双螺旋桨尾流进行图像采集,利用MATLAB软件对图像进行灰度处理,并对图像进行了灰度的扩展,并转换灰度直方图,最终通过对实验结果进行分析,得到了三者之间不同灰度级别下的频数分布规律。用Canny算法进行弱边缘检测并得出实验结论。结论对进一步尾流图像信息化研究提供基础。第二,系统的阐述分析了机载磁传感器探测尾流电磁场的基本理论和水上船舶运动导致的磁异常检测基本理论,并建立了数学模型。第三,从麦克斯韦方程组和磁流体动力学基本方程出发,推导分析了电磁尾流在地磁场中引起磁异常的计算方法和求解方法。在特定条件下,对船舶尾流不同下游距离的磁异常进行了计算和分析,结果表明：随着尾流下游距离的增加,磁场强度均越来越弱,在最初的4km以内磁场强度急剧降低,在5km~12km较缓慢降低,超过20km以后磁异常变化越来越小,两者近似呈反比关系；该结果还表明,尾流下游距离在20km以内时,则磁场强度计算结果在0.17×10-4A/m～2.2×10-4A/m之间,可被磁力仪有效探测。
[Abstract]:When a ship moves on the sea, it produces a wake in the opposite direction of motion, that is, the ship's wake. The wake is caused by the disturbance of the ship hull and propeller to the sea water, forming a bubble curtain belt with various physical properties. Influenced by weather, air temperature, water temperature, sea area, speed and so on, the wake has different physical and physical characteristics. Studying these characteristics and characteristics can map out the information of the ship itself, such as type, tonnage, speed, etc., to the military, Ocean observation and other fields are of great significance. The main contents of this paper are the electromagnetic properties of ship wake bubble curtain, including the following aspects: first, using the self-developed experimental device to simulate the formation of wake bubble curtain, on the basis of which, The single propeller wake and the double propeller wake are collected, the image is processed with MATLAB software, and the gray scale is extended, and the gray histogram is transformed. Finally, the experimental results are analyzed. The frequency distribution law of different gray levels among the three is obtained. The Canny algorithm is used to detect the weak edges and the experimental results are obtained. Conclusion it provides a basis for further research on wake image informatization. Secondly, the basic theory of detecting wake electromagnetic field by airborne magnetic sensor and the basic theory of detecting magnetic anomaly caused by ship motion on water are analyzed systematically, and the mathematical model is established. Thirdly, based on Maxwell's equations and the basic equations of magnetohydrodynamics, the calculation method and solution method of magnetic anomaly caused by electromagnetic wake in geomagnetic field are deduced and analyzed. Under certain conditions, the magnetic anomalies of different downstream distances of ship wake are calculated and analyzed. The results show that with the increase of downstream distance of wake, the intensity of magnetic field becomes weaker and weaker, and the intensity of magnetic field decreases sharply within the initial 4km. The results show that the magnetic field intensity is between 0.17 脳 10-4A/m~2.2 脳 10-4A/m and 0.17 脳 10-4A/m~2.2 脳 10-4A/m when the downstream distance of wake is within 20km. It can be effectively detected by magnetometer.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U661

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