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，其中大多数是由多个垂直圆柱体构造的，在波浪和电流的环境中工作。为了评估作用在海洋结构上的流体动力，必须考虑波浪与电流之间的相互作用以及多个气缸之间的相互作用。一旦计算了由波和电流引起的波浪漂移力，我们就可以获得波漂移舞，该波浪在不规则波中系泊的浮动体的缓慢漂移运动中起着重要作用。在本研究中，假定当前的速度很小（与波的相速度相比）。研究了电流的影响以及圆柱体附近的相互作用波的重要性。研究结果如下。1。建立了数学模型，该模型考虑了在波和电流中固定或振荡的多个圆柱体之间的相互作用。获得半分析溶液。开发了基于上述理论的计算机程序……可以计算出不同的电流速度，波频，波动方向，圆柱数和排列的第一阶和二阶流体动力。2。为了验证理论和计算结果，进行了波动箱中的实验。实验结果与计算出的结果非常吻合。3。稳定的灾难流动（由电流引起的）对二阶力（例如波漂移力和波浪漂移阻尼）具有很强的影响。4。剥削性波的影响无法忽略从气缸中散布的剥削波的影响。5。浮动体的振动对频率的第二阶稳定效应，并在频率范围内具有强大的效应。（KC数），波漂移阻尼（由潜在理论计算）在慢速运动阻尼中非常重要。将来，上述理论扩展以应用于任意形状的身体。将开发计算机程序，并将进行实验以验证理论并计算结果。较少的