零方程湍流模型用于城市微气候的模拟研究

Numerical simulation of the micro climate urban environment using a zero-equation turbulence model

室外微气候环境对城镇人居环境和建筑能耗有重要影响,数值模拟技术作为快速的预测方法能有效评价社区规划的优劣。文章选用风洞实验数据对湍流涡粘度表达式进行优化,提出新的零方程湍流模型(ZeroEQ),并与两方程湍流模型(MMK)、大涡模拟(LES)和风洞实验数据进行对比分析;通过对寿安新城区零方程湍流模型的应用分析,探讨该模型应用于实际工程项目的可行性。结果表明:在同等计算机配置下,Zero-EQ模型比MMK模型快60%,是LES模型计算所需时间的1/15,能有效地预测不规则建筑群的流场分布;通过分析不同地形区域的风热环境特点,Zero-EQ模型可快速预测城镇微气候环境,为城区规划设计提供合理建议。

The micro climate urban environment has an important effect on outdoor residential environment and building energy consumption. Numerical simulation as a fast prediction method can effectively evaluate the quality of neighborhood planning. In this paper,a rapid and relatively reliable Zero-equation turbulence model（ Zero-EQ） is provided through analyzing and improving measurement data of the wind tunnel experiment,and compared with two-equation turbulence model（ MMK）,Large Eddy Simulation（ LES） and a wind tunnel experiment. By investigating the application of ZeroEQ model in Shouan Town,this research discusses the feasibility of the model＇s application to the real project. The result shows that the computational speed of Zero-EQ model is faster by 60% than MMK model,and only 1 /15 of that using LES model under the same computational resources,indicating the capability of Zero-EQ on relatively accurately predicting the wind flow field in a complex neighborhood. In the end,Zero-EQ can quickly predict the micro climate urban environment and provide reasonable suggestion for the urban planning and design by means of studying the wind and thermal environment over different urban terrains.