考虑流固耦合的近海风机动力响应数值计算

研究了固定式海上风机的流固耦合问题.选取美国可再生能源实验室(NREL)建立的5 MW海上单桩式风机模型,采用Kaimal谱和风剪切指数理论模型,通过NREL编写的程序—TurbSim,生成脉动风场,进而使用气弹程序FAST计算风力机的气动荷载,输出包括剪力和弯矩在内的塔顶荷载时程.选取Pierson-Moskowits波浪谱,并利用谐波叠加法模拟随机波浪.采用Morison公式计算波浪力,分别建立了海上风机塔架考虑与不考虑流固耦合效应时的动力方程及数值模拟方法,并对比分析了这两种情况下的波浪力和结构响应的差异.结果表明,两种情况下计算得到的波浪力和风机响应有明显差异,并且这种差别跟风浪大小等因素有关.

Numerical Simulation of Dynamic Response for Offshore Wind Turbines including Fluid-Structure Interaction

This paper investigated the issue of fluid-structure interaction (FSI) for fixed offshore wind turbines. The model for a 5 MW monopile wind turbine built by the National Renewable Energy Laboratory (NREL) was selected as an example. The stochastic inflow turbulence code written by NREL-TurbSim, the Kaimal spectrum and exponential wind profile were used to generate stochastic and full field turbulent wind. The aeroelastic code FAST developed by NREL was then used to calculate the aerodynamic load on the wind turbine. The time histories of shear force and bending moment at the top of the tower were obtained. The random wave was simulated using the Pierson-Moskowits spectrum through the harmony superposition method. Two cases were considered in this study, namely, the case that considered the effect of FSI and the case in which the effect of FSI was neglected. Kinematic equations and numerical models under the two cases were developed respectively, and the comparison between the two cases was made to investigate the effect of FSI. The results indicate that distinct deviations affected by the intensity of the wind and wave exists in both wave force and dynamic responses in the two situations.