基于LES的风机尾流湍流特性仿真研究

Turbulence Characteristics of Wind Turbine Wake Based on Large Eddy Simulation

针对风力机运行过程中尾流对大气边界层的湍流特性影响,采用非稳大涡模拟方法结合大气湍流理论,引入UDF函数对Fluent软件进行二次开发,加载大气边界层风廓线函数和温度分布函数,建立风机及周围流场模型,对尾流区域的风速、温度、湍动能开展仿真对比分析。仿真结果表明,非稳大涡模拟能够较为精确的解析叶片尾流湍流特性。大气流经叶片后,其风速、温度、湍动能变化趋势大致相同,但在不同层结下的变化幅值略有不同。在不同温度层结下,风机尾流对大气边界层内产生了较为明显的温度波动。在不同稳定层结下,近尾流区的温度变化幅度明显小于周围大气温度的变化幅度。

The influence on the turbulence characteristics of wind turbine wake of atmospheric boundary layer during the wind turbine operation was considered in this paper.By establishing the wind turbine and the surrounding flow field model,using the unsteady large eddy simulation method combined with the atmospheric turbulence theory,the UDF function was introduced to the Fluent software for development.The wind profile function and the temperature distribution function of the atmospheric boundary layer were loaded,and the wind speed,temperature,and turbulent kinetic energy were simulated as well as the comparative analysis was also conducted.The unsteady large eddy simulation method was proved to be precise on the description on the turbulence characteristics of wind turbine wake.The results show that the trend of the change of the wind speed,temperature,and turbulent kinetic energy is approximately similar after the wind passes through the wind turbine,however,the changes in the different layers differ slightly.The influence on the temperature variations in the atmospheric boundary layer will occur due to the various vertical distribution of temperature in different layers.However,there exist obvious temperature variations at different layers,and the temperature variations near the wake area are smaller than those of the ambient area under different stable layers.