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采用FLUENT软件中的用户自定义函数功能和动网格功能进行造波和消波,采用VOF方法捕捉自由液面,开发了一个数值波浪水池,该水池可以生成规则波浪、按照波谱生成不规则波浪以及生成既定的不规则波波列.文中开展了网格和时间步长试验,力图找到经济精确的网格划分方案和高效的时间步长方案.文中按照Jonswap谱进行了不规则波浪的数值模拟,采用了等分能量法分解波谱的频率区间来得到组成波的圆频率,模拟结果显示计算波谱与目标波谱一致,波浪的统计特征得到了很好的体现,模拟不规则波波谱的缺点是耗时过长.由于真实海况下对海洋浮式结构物造成损坏的往往不是整个波浪时间序列,而是少数的几个大波或者波列中的波群.因此采用CFD方法准确模拟出既定的波列将会对了解极端海况下海洋结构物的损坏事故提供极大帮助.采用本文提出的方法成功模拟出了既定的极大波,这个方法的关键在于确定造波板的运动规律.类似按照波谱造波,文中将造波板处的波浪时历进行了分解,得到了若干个小振幅波,通过傅里叶级数法推导出了每个小振幅波的特征参数.同样采用水力传递函数确定每个小振幅波对应的推板振幅,之后将这些组成波对应的推板运动规律进行叠加得到了模拟不规则波波列时需要的推板运动规律.
Using user-defined function in FLUENT software and moving grid function to make wave and eliminate wave, using VOF method to capture free surface, we developed a numerical wave pool, which can generate regular wave and generate irregular wave according to spectrum As well as to generate the irregular waves.The author carried out grid and time-step experiments in an effort to find an economical and accurate meshing scheme and an efficient time-step scheme.The numerical simulation of irregular waves according to the Jonswap spectrum , The frequency interval of the spectrum is decomposed by the method of dividing energy to obtain the circular frequency of the component wave. The simulation results show that the calculated spectrum is consistent with the target spectrum, and the statistical characteristics of the wave are well represented. The disadvantage of the simulated irregular wave spectrum is loss Time is too long.Due to the fact that the damage to the marine floating structure under the real sea condition is not the whole wave time series but a few wave groups in large waves or wave groups, CFD method is used to accurately simulate a given wave train Will be very helpful to understand the damage caused by marine structures in extreme sea conditions.Using the method proposed in this paper to successfully simulate The key of this method is to determine the motion law of the wave plate.According to the wave making wave, the wave time history of the wave plate is decomposed and several small amplitude waves are obtained, The series method deduces the characteristic parameters of each small amplitude wave, and also uses the hydraulic transfer function to determine the amplitude of the push plate corresponding to each small amplitude wave, and then adds the law of the push plate motion corresponding to these component waves to obtain the simulation irregularity Bobo column need to push the law of movement.