THE PREDICTION OF WAVE-INDUCED MOTION AND MOORING FORCES FOR FLOATING OFFSHORE STRUCTURES

海上浮动结构的波感运动和系泊力的预测

基本信息

批准号：
61460177
负责人：
MATSUI TETSUYA
金额：
$ 4.61万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-61460177/
关键词：
Floating offshore structures Irregular waves Moored vessel Wave drift force 長周期運動

项目摘要

A series of theoretical and experimental investigations have been conducted to predict the slow drift motion and mooring line forces for floating structures in irregular sea waves. The resluts obtained from this project are summarized as follows:(1) An exact method for simulating the slow drift motion and mooring line forces for floating offshore structures has been proposed within the framework of the second order potential flow theory. The method has been applied to understand the slow drift behaviour of such structures as an articulated column and a moored semi-submersible. It was confirmed that the simulated time histories of the slow drift motion of the semi-submersible are in fairly good agreement with the measured ones in model tests, if the viscous damping term is evaluated appropriately, say by means of the Morison formula.(2) A specific instrument for the random forced oscillation test has been manufactured to measure the hydrodynamic forces on an articulated column model in the low frequency motion. The effects of the high frequency motion of the column and the incoming waves on the hydrodynamic forces have been investigated in dateil. The conclusions arising from the test are listed in the following:a) The hydrodynamic damping of the articulated column in the low frequency motion is mainly due to viscous effects.b) Such damping forces are strongly influenced by the presence of the high frequency motion of the column as well as the incoming waves. Due to small number of the measured data their significant scatter observed. it is difficult at the present stage to predict quantitatively the hydrodynamic forces on the column in the low frequency motion. This will be a matter for future research.

为了预测不规则海浪中漂浮结构的缓慢漂移运动和系泊线力，进行了一系列理论和实验研究。本课题取得的成果概括如下：(1)在二阶势流理论框架内提出了一种精确模拟浮式海上结构物慢速漂移运动和系泊线力的方法。该方法已应用于了解铰接柱和系泊半潜式潜水器等结构的缓慢漂移行为。经证实，如果粘性阻尼项通过莫里森公式计算得当，半潜式钻井平台慢漂运动的模拟时程与模型试验中的实测时程具有很好的一致性。(2 ) 已经制造了一种用于随机受迫振动测试的专用仪器，用于测量低频运动中铰接柱模型上的水动力。柱的高频运动和传入波浪对水动力的影响已在 dateil 中进行了研究。试验得出的结论如下： a) 铰接柱在低频运动中的流体动力阻尼主要是由于粘性效应。 b) 这种阻尼力受到铰接柱高频运动的强烈影响。柱以及传入的波。由于测量数据数量较少，观察到了显着的分散。现阶段很难定量预测低频运动中立柱所受的水动力。这将是未来研究的一个问题。