【作者】 刘晨祥； 陈诚； 张显涛； 郭孝先； 刘磊；

【Author】 LIU Chen-xiang;CHEN Cheng;ZHANG Xian-tao;GUO Xiao-xian;LIU Lei;State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University;Sanya Yazhou Bay Deep Sea Technology Research Institute,Shanghai Jiao Tong University;

【机构】 上海交通大学海洋工程国家重点实验室； 上海交通大学三亚崖州湾深海科技研究院；

【摘要】 在极端波浪下,海洋平台容易遭遇甲板上浪问题,对平台上结构物造成剧烈砰击。为简化起见,通常采用溃坝模型来模拟甲板上浪流动。本文采用聚焦波模拟极端波浪,用悬空平板模拟海洋平台,基于计算流体力学（CFD）方法开展数值模拟,探究甲板上浪后流体的流动机理。针对CFD模拟结果,以平板前缘最大上浪高度作为等效坝高,同时考虑上浪水流的水平速度,修正经典溃坝模型来预报上浪水流的水平砰击载荷（或动量通量）。研究表明,当相对越浪时间（■,t₀为越浪持续时间,h₀为溃坝模型中的坝高,g为重力加速度）较大时,考虑水平速度影响的改进型溃坝模型能够较为准确地预报水平砰击载荷（或动量通量）;当相对越浪时间较小时,改进型溃坝模型低估了砰击载荷。造成这种现象的原因是当相对越浪时间较小时,甲板上浪后的垂向速度分量占比比较大,最终也会转变成水平动量通量,而这部分影响并未在改进型溃坝模型中予以考虑。更多还原

【Abstract】 Under extreme waves,ocean platforms are prone to green water events,causing violent impact loading onto structures on the platform.For simplicity,the dam-break model is usually used to simulate the flow of waves on the deck.In this paper,focused waves are used to simulate extreme waves,suspended flat plates are used to simulate ocean platforms,and numerical simulations are carried out based on computational fluid dynamics（CFD） methods to explore the flow mechanism of fluids on deck after waves.Based on the CFD simulation results,the maximum wave height on the front edge of the plate is taken as the equivalent dam height,and the horizontal velocity of the wave is considered,and the classical dam break model is modified to predict the horizontal impact load（or momentum flux） of the water flow on deck.Research shows that when the relative duration（■,t₀ is the wave-overtopping duration,ho is the dam height in the dam-break model,and g is the gravitational acceleration） is relatively large,the improved dam-break model that takes into account the influence of horizontal velocity can predict the horizontal impact loading（or momentum flux） more accurately.When the relative duration is small,the improved dam break model underestimates the horizontal impact loading.The reason for this phenomenon is that when the relative duration is small,the vertical velocity component after the wave on the deck takes up a larger proportion,and it will eventually be transformed into a horizontal momentum flux,and this part of the impact is not considered in the improved dam break model.更多还原