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Development of GPS Measurement System and Characteristics Analysis for Long Period Gravity Wave That Induces Long Period Oscillation of Water Surface in Harbour

引起港口水面长周期振荡的长周期重力波GPS测量系统研制及特性分析

基本信息

批准号：
15360466
负责人：
KOUGUCHI Nobuyoshi
金额：
$ 9.09万
依托单位：
Kobe University (2004-2006)神戸商船大学 (2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

项目摘要

When a harbor is designed, a general gravity wave (period about 0.1-10 second degree) causes various problems, but concerning about it some countermeasures are considered by marine engineering and results of research of civil engineering, and a considerable part is already solved. However a ship anchored or moored in a harbor is pitched and rolled by a long period gravity wave (for period dozens of seconds, several minutes), it's countermeasure cannot be still enough, and now some problems on a mooring line strength and cargo handling work are still remained. Such a long period wave (for the amplitude is less than dozens of cm, a period, about dozens of seconds, several minutes) that is propagated from the open sea and coastal waters area includes the following problems.(1) A strong detachment and early flow are caused in harbor mouth neighborhood by long water particle exercise orbit of a long period surge, and they cause a harbor burying by drifting sand of bottom of the sea.(2) By a … More strong detachment and early flow near harbor mouth, it causes a serious and security problem on a ship navigating a narrow area near harbor mouth.(3) Wave energy of a long period gravity wave has a small propagation and reflection decrement, and after incidence to a harbor a greater part of the wave energy is kept and it may grow in the case of resonance with the harbor inherent frequency.Then a dangerous pitching and rolling movements for a mooring or anchoring ship in the harbor are caused by it. These serious problems for harbor design and the anchorage in a harbor caused by such a long period wave is beginning to examine. There development of a study for a long period wave is expected immediately, because the cause and characteristics of a long period wave are not made clear yet.In particular it is appear that a study to make clear the causes and the characteristics of a long period gravity wave on the basis of an observation fact is important. However it is difficult that the measurement is done by conventional wave observation technology, because a period of the long period gravity wave is too long and amplitude of it is too small compared with a normal gravity wave.Therefore in this research arrayed wave observation buoys system whose 3 dimensional movements are measured precisely by the Carrier-Phase Differential GPS is proposed. In this proposed system, a wind wave direction which is observed in before Cloverleaf-Buoy and a 3 dimensional wave information of a long period wave are measured precisely. And an evaluation of effectiveness was carried out by the experiment on land and some computer simulations. As using this proposed system, it made clear the cause and characteristics of a long period gravity wave and solve some problems about a ship's mooring and anchoring or harbor design.In near future, we will be able to clear the characteristics of the long period gravity wave and some problems about safety of port and mooring ship according to the long period gravity wave with the use of our proposed GPS Measurement System. Less

一般重力波（周期约0.1-10秒）在港口设计时会引起各种问题，但有关这方面的对策，海洋工程和土木工程的研究成果已作了考虑，相当一部分已得到解决。然而，在港口锚泊或系泊的船舶在长周期重力波作用下（几十秒，几分钟）会发生纵摇和横摇，其对策还不够，目前还存在着一些系泊缆强度和装卸作业的问题。从公海和沿海沃茨区域传播的这种长周期波（对于振幅小于几十厘米、一个周期、大约几十秒、几分钟）包括以下问题。(1)长周期涌浪的长水质点运动轨迹在港口附近造成强烈的滑脱和早流，造成海底流沙埋港。(2)由 ...更多信息强脱体和港口附近的早流，给船舶在港口狭窄水域航行带来了严重的安全问题。(3)长周期重力波的波能传播和反射衰减较小，波浪入射到港口后，大部分波浪能量被保留下来，在与港口固有频率共振的情况下，波浪能量可能会增长，从而引起港口内系泊或锚泊船舶的危险纵摇运动，这些都给港口设计和港口锚地带来了严重的问题如此长周期的波浪正在开始被审视。由于长周期重力波的成因和特征还不十分清楚，因此，开展长周期重力波的研究迫在眉睫，特别是根据观测事实弄清长周期重力波的成因和特征显得尤为重要。然而，由于长周期重力波的周期太长，振幅太小，常规的波浪观测技术很难进行测量，因此本研究提出了利用载波相位差分GPS精确测量长周期重力波三维运动的阵列式波浪观测浮标系统。在该系统中，可以精确地测量出在立体式浮标前观测到的风浪方向和长周期波浪的三维波浪信息。并通过陆上试验和计算机模拟对该方法的有效性进行了评价。该GPS测量系统的应用，使长周期重力波的成因和特征得到了明确，解决了船舶系泊、锚泊和港口设计中的一些问题，在不久的将来，我们还可以利用GPS测量系统来了解长周期重力波的特征，以及长周期重力波对港口和系泊船舶安全的影响。少