基于修正参数k-l湍流模型的复杂地形流动研究

NUMERICAL SIMULATION OF FLOW OVER COMPLEX TERRAIN BASED ON MODIFIED k-l TURBULENCE MODEL

针对风资源精细化评估需求,提出采用实际测风数据修正k-l湍流模型的关键参数,以提高数值仿真对大尺度复杂地形流动的准确性和适用性。在此过程中,首先介绍k-l模型的求解过程并开展网格分辨率研究;其次利用实际测风数据修正模型参数并使用典型案例进行验证;最后以中国华南地区某实际风电场为对象,将其与k-ε模型进行对比分析以验证其有效性和优越性。结果表明,相比于k-ε模型,原始k-l模型由于高估了尾流影响,导致预测误差偏大;而修正参数后的k-l模型能有效提升精度,风加速因子和发电量等效小时数的平均相对误差分别降低5.1%和7%。因此,在k-l模型的实际应用过程中,需利用实际测风数据修正参数,或将参数B1的量级调整为102。

In view of the demand for high accuracy of wind resource assessment,key parameters of the k-l turbulence model are modified using measured data.By adopting this methodology,the accuracy and practicality of numerical simulation for large-scale flow over complex terrain can be improved dramatically.First,the k-l turbulence model is reviewed,and appropriate grid resolution is determined.Then,the model parameters are modified based on measured data and verified using a benchmark case.Finally,a wind farm in South China is evaluated using different models to verify the effectiveness and superiority of the proposed method.The results indicate that wake effect is overestimated when the original parameters of k-l turbulence model are used,which leads to increased error.The accuracy of k-l turbulence model is improved using the parameters determined by the proposed method.The mean relative error of wind speed-up factors and AEP(Annual Energy Production)are reduced by 5.1%and 7%,respectively.In summary,the parameters of the k-l turbulence model should be modified using measured data or the order of parameter B1 should be modified to 102.