基于自主软件LSWS的典型地形大气CFD模式研究与应用

Research and application of an atmosphere CFD model for typical terrains based on self-developed LSWS software

基于我国典型地形风资源评估、风电场微观选址及风电预测等的发展要求,根据风场实测数据,提出了两种风廓线模型:一种是利用实测数据修正的Gryning风廓线模型,另一种是结合分段函数及理论公式拟合的风廓线模型。考虑大气热效应、地转效应等大气效应,结合改进的雷诺时均k-ε两方程湍流模型,建立了能够模拟不同大气稳定度的典型地形大气CFD模式,开发了自主可控的风场CFD模拟软件LSWS(large scale wind simulation)。以锡林浩特平坦草原地形和山西丘陵地形的风场为例,比较了自主软件LSWS和商业软件Fluent的模拟精度。模拟结果显示:对于锡林浩特平坦草原地形风场,两个软件模拟结果与实测数据总体吻合良好;在稳定大气状态下,LSWS的计算精度较Fluent最大提升6.33%;在模拟山西丘陵地形时,LSWS的计算精度明显高于Fluent,特别是绕山脊的山后流场模拟更加合理,LSWS计算精度较Fluent最多提升40%以上。

In order to meet the development requirements of wind resource assessment of typical terrains,wind farm micro-siting and wind power prediction,two wind profile models are proposed based on measured wind field data:one is the modified Gryning wind profile model;the other is the fitted wind profile model by using the piecewise function and theoretical formula.Considering the atmospheric thermal and geostrophic effects,and combined with the modified k-εmodel for Reynolds-Averaged Navier-Stokes(RANS),an atmospheric CFD model is proposed to simulate the wind field of complex terrains under different atmospheric stable states,thus a CFD software of LSWS(large scale wind simulation)for the wind field simulation is developed.The simulation accuracy of the self-developed LSWS software is compared with that of the commercial software Fluent,based on the wind test data from the Xilinhot flat terrain and the Shanxi hills.The results show that the simulation data of the two softwares are in good agreement with the measured data of the Xilinhot flat terrain.The computational accuracy of the self-developed LSWS software is 6.33%higher than that of the Fluent software under stable atmospheric states.The computational accuracy of the self-developed LSWS software is significantly higher than that of the Fluent software,especially in simulating the wind field behind the Shanxi hills,and the computational accuracy is at most 40%higher than that of the Fluent software.