考虑流固耦合的近海风电支撑体系自振特性分析  

Analysis of Dynamic Characteristics of Offshore Wind Power Foundation with Consideration of Fluid-Structure Interaction

作　　者：田树刚[1] 陈清军[1] 

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《力学季刊》2014年第3期473-481,共9页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金重大研究计划项目(91315301)

摘　　要：近海风电支撑结构的自振特性是此类结构抗震设计的基础.以某海上风电场1.5MW风电基础支撑体系为背景,考虑流固耦合效应,采用有限元方法对近海风电支撑体系的自振频率和振型进行了计算分析.文中首先将单桩无水工况的数值结果与解析结果做了比较,验证了本文有限元模型的准确性.在此基础上,分单桩有水、单桩无水、四桩有水和四桩无水四种工况进行了支撑体系的自振特性分析,给出了前十阶自振频率和振型,探讨了势流体水层对近海风电支撑体系自振特性的影响.结果表明:水层的存在对单桩体系的前两阶自振频率以及四桩体系的前四阶自振频率影响甚小;总体而言,水层对单桩体系三阶以后的自振频率的影响要明显大于对四桩体系五阶以后的自振频率的影响;本文选取的近海风电支撑体系的各阶频率均能有效避开马达转动频率和叶轮扫略频率.The dynamic characteristics analysis of offshore wind power support system is the precondition of seismic design of such structures. Based on the actual offshore wind turbine of 1.5MW, and with the consideration of Fluid-structure interaction, the natural frequencies and modes of offshore wind power support system were analyzed with the use finite element method. Firstly, a comparison of single pile system without the consideration of water was given between finite element model and analytical solutions to verify the accuracy of the finite element model. Based on the above result, four conditions of support system were established which were single pile system, single pile system with consideration of water, four pile system and four pile with consideration of water, then the first ten modes and natural frequencies of the above mentioned models were given, and the effect of water on the vibration characteristics of the system were demonstrated. The results show that the water have little effect on the first two natural frequencies of single pile system and the first four natural frequencies of four pile system; the effect of water on the higher order frequencies （higher than three） of single pile system were larger than it on four pile system （higher than five）. The natural frequencies of the four support systems could avoid the 1P and 3P frequency.

关 键 词：近海风电 势流体 流固耦合 自振特性 数值分析 

分 类 号：TU475[建筑科学—结构工程]