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Hydrodynamic interaction of multiple-cylinders oscillating in both current and waves

多圆柱体在水流和波浪中振荡的水动力相互作用

基本信息

批准号：
05650949
负责人：
BAO Weiguang
金额：
$ 1.47万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650949/
关键词：
Wave drift damping Wave drift force Slow drift motion Nonlinear wave load 浮体干渉流体力

项目摘要

Ocean structures, most of which are constructured by multiple vertical cylinders, are working in an environment of both waves and current. In order to evaluate the hydrodynamic forces acting on the ocean structures, the interaction between the waves and current as well as between multiple cylinders has to be considerded. Once the wave drifting force caused by waves and current is calculated, we can obtain the wave drift damping which plays an important role in the slow drift motion of floating body moored in irregular waves. In the present research, the current velocity is assumed to be small (compared with the phase velocity of waves). The effect of the current and the importance of the interaction waves near the cylinders are investigated. The research results are as follows.1.A mathematical model is established, which takes account of interaction among multiple cylinders fixed or oscillating in both waves and current. A semi-analytical solution is obtained. A computer program based … More on the above theory is developed, which can calculate the first and second order hydrodynamic forces for different current velocity, wave frequencies, wave direction, cylinder number and arrangement.2.In order to verify the theory and calculated results, experiments in wave tanks were carried out. The experimental results are in good agreement with the calculated ones.3.The steady disturbance flow (caused by the current) has a strong effect on the second order forces such as wave drift force and wave drift damping.4.The effect of evanescent waves scattered from cylinders can not be neglected.5.The oscillation of the floating body has a strong effect on the second order forces near the resonance of the oscillation.6.In a certain range of wave frequencies and wave heights (Kc number), the wave drift damping (calculated by the potential theory) is very important in the damping of slow drift motion.In the future, the above theory is expanded to be applied to the arbitrary shaped bodies. The computer program will be developed and experiments will be carried out to verify the theory and calculated results. Less

海洋结构物大多数是由多个垂直圆柱体组成，它们在波浪和水流的共同作用下工作。为了计算作用在海洋结构物上的水动力，必须考虑波流相互作用以及多个圆柱体之间的相互作用。通过计算波浪和海流共同作用下的波浪漂移力，可以得到对不规则波中系泊浮体慢漂运动起重要作用的波浪漂移阻尼。在本研究中，流速被假定为小（与波的相速度相比）。研究了水流的影响以及圆柱体附近相互作用波的重要性。主要研究成果如下：1.建立了考虑波浪和水流共同作用下多个固定或摆动圆柱相互作用的数学模型。得到了半解析解。一种基于 ...更多信息在此基础上，建立了一个计算波浪力的数学模型，该模型可以计算不同流速、波浪频率、波浪方向、圆柱数和波浪力的一阶和二阶水动力。2.为了验证理论和计算结果，进行了波浪水槽试验。实验结果与计算结果吻合较好（由电流引起）5.浮体的振荡对振荡共振附近的二阶力有很大的影响; 6.浮体的振荡对二阶力有很大的影响; 7.浮体的振荡对二阶力有很大的影响; 8.浮体的振荡对二阶力有很大的影响; 9.浮体的振荡对二阶力有很大的影响在一定的波频和波高（Kc数）范围内，波浪漂移阻尼（由位势理论计算）在慢漂移运动阻尼中起着重要作用，今后将把该理论推广到任意形状的物体。为了验证理论和计算结果，将编制计算机程序并进行实验。少