漂浮式风力机半潜式平台摇荡运动混沌特征分析

Analysis of the Swaying and Sloshing Movement Chaos Characteristics of the Semi-submersible Type Platform of a Floating Type Wind Turbine

针对漂浮式风力机半潜式平台在复杂海洋环境下的摇荡运动所表现出的复杂非线性特征，建立半潜式平台的NREL5Mw漂浮式风力机模型，基于辐射／绕射理论并结合有限元方法得到了平台摇荡运动时间序列数据。基于混沌理论，应用功率谱分析、相空间重构及最大Lyapunov指数3种方法从定性和定量的角度，对摇荡运动时间序列数据进行了混沌特征分析。结果表明：平台摇荡运动时间序列数据具有明显的混沌特征，其最大Lyapunov指数不同（在0．05-0．09之间小幅变化）；平台摇荡运动时间序列数据具有短期可预测性，且其最大可预测时间不同，最大可预测时间均不超过17s。

In the light of the complex non-linear characteristics of the semi-submersible platform of a floating type wind turbine displayed in the swaying and sloshing movement under the condition of the complicated oceanological environments, established was a model for a NREL 5 MW floating type wind turbine on a semi-submersible platform and obtained were the time sequence data of the swaying and sloshing movement of the platform based on the irradiation/diffraction theory coupled with the finite element meth- od. Based on the chaos theory, three methods such as power spectrum analysis, phase space restructuring and maximum Lyapunov index method were used to perform an analysis of the chaos characteristics of the swaying and sloshing movement time sequence data from the viewpoints of qualitation and quantification. It has been found that the swaying and sloshing movement time sequence data of the platform have obvious chaos characteristics and their maximum Lyapunov indexes are different （ varied in a range from 0.05 to 0.09 ）. The swaying and sloshing movement time sequence data of the platform boast a short term predicable nature and their maximum predicable time durations are varied and all of them will not exceed 17 seconds.