极浅水单点系泊FPSO低频响应分析  

Analysis on the low frequency response of a single point moored FPSO in ultra-shallow water

作　　者：肖龙飞[1] 杨建民[1] 胡志强[1] 

机构地区：[1]上海交通大学海洋工程国家重点实验室,上海200030

出　　处：《船舶力学》2010年第4期372-378,共7页Journal of Ship Mechanics

基　　金：国家自然科学基金项目(50879045);上海市自然科学基金项目(07ZR14048)

摘　　要：对单点系泊FPSO在极浅水中波浪作用下的低频响应进行频域数值计算与模型试验研究,水深16.7m,入射波有义波高4.1m。计算结果与试验结果符合良好。试验中的波浪校验结果显示,在不规则波浪谱中出现明显的低频成分。由此产生了一阶低频波浪力,其能量谱是通常二阶波浪力谱的近百倍,导致FPSO在极浅水中所受低频波浪力大大增加,并引起极大幅度的共振纵荡运动响应。极浅水时,低频纵荡运动响应主要是一阶的,二阶成分几乎可以忽略,而且与深水相比,由于阻尼和二阶波浪力同时增加,二阶响应变化不大。低频浅水长波和一阶低频波浪力及其诱导大幅运动响应会给极浅水FPSO和系泊系统设计带来严重影响,在水动力性能预报时必须仔细予以考虑。The low frequency （LF） response of a single point moored FPSO exposed to irregular waves in ultra-shallow water is investigated by conducting frequency, domain computations and wave basin model tests. The water depth is 16.7m and the incident wave height is t! =4.1m. It is shown that the agreement of results between calculation and experimentation is good.In terms of the measured wave spectrum by wave calibration in the wave basin, it can be seen that an obvious LF part appears. As a result, the first order LF wave force exists and is much larger than the second one. The difference of the spectrums is about one hundred times. The LF wave drift force increases enormously. Consequently, much larger resonant surge response is induced. The surge response is almost the same as the first order one and the second order one is almost negligible.The second order response changes indistinctively with the decrease of the water depth, since both the second order wave force and the damping increase.Therefore, in ultra-shallow water,LF part of incident waves should be taken into account carefully in the prediction of the hydrodynamic response of a single point moored FPSO due to the very serious wave induced LF response.

关 键 词：FPSO 极浅水 低频响应 波浪力 纵荡 

分 类 号：U674.381[交通运输工程—船舶及航道工程]