水下桩腿长度对带支腿浮式结构水动力系数的影响分析  

The effect of the underwater leg length on hydrodynamic coefficients of the floating structure with legs

作　　者：陈徐均[1] 武海浪[1] 黄亚新[1] 

机构地区：[1]中国人民解放军理工大学野战工程学院,南京210007

出　　处：《水动力学研究与进展（A辑）》2014年第1期83-92,共10页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金(51379213);江苏省自然科学基金(BK2011121);国家工信部高性能船舶科研项目~~

摘　　要：风电安装船是带支腿浮式结构,而水下桩腿长度对船体在波浪中的动力响应会产生较大的影响。究其原因就是水下支腿的存在导致结构所受水动力不同于普通无支腿船体。为了研究水下桩腿长度对水动力系数大小的影响,该文利用三维势流理论对桩腿收放过程中不同阶段的水动力系数进行了数值计算,给出了不同工况下带支腿浮式结构在波浪中运动的6个自由度水动力系数与波浪频率的关系。研究结果表明:桩腿水下长度对带支腿浮式结构水动力系数的影响较为明显,除垂荡运动外,附加质量随桩腿在水下的长度的增加而增大;当波浪频率处于低频或高频时,桩腿的水下长度对附加阻尼的影响较小,而当波浪频率处于中频时,附加阻尼系数随运动状态的不同表现出不同的规律。此外,还分析了桩腿对带支腿浮式结构湿固有频率的影响,结果反映出桩腿在水下的长短对结构的湿固有频率有明显的调制作用。The wind farm installation vessel is a floating structure with multi legs. The underwater leg length have a prominent effect on the responses of the vessel in waves. The main factor is that the existing of the underwater legs leads to the hydrodynamic forces different from the normal vessel without legs. To analyze the influence of the underwater leg length on the hydrodynamic characteristics, the different stages are classified according to the length of the underwater legs and the hydrodynamic coefficients of the structure in different stages are calculated by using the potential theory. The relations betweenthe hydrodynamic coefficients of the 6 DOFs and the wave frequencies are presented. The results show the underwater leg length obviously affect the hydrodynamic coefficients of the multi-leg structure except for the heave, the added mass increases when the legs protract toward the water. When the wave frequencies locate on the low or high frequencies region, there is little effect of the legs＇ length underwater on the added damping. When the wave frequencies locate on intermediate frequency region, the added damping appears different characters according to the different motion. Further more, the effect of the legs on the wetted natural frequencies is discussed. The underwater length of legs has an obvious effect of modulating the wetted natural frequencies of the structure.

关 键 词：海洋工程 带支腿浮式结构 桩腿 水动力系数 湿固有频率 

分 类 号：TV148[水利工程—水力学及河流动力学]