街谷结构内流场和污染浓度场的数值模拟研究

从三维尺度出发,对6种不同几何尺寸的街谷结构内流场和污染浓度场进行了数值模拟.流场计算模型采用Spalart-Allmaras湍流模型,污染物浓度场采用与流场耦合的对流扩散方程模拟,采用有限元方法离散微分方程.模拟结果表明,街谷结构的几何尺寸对其中流场和污染场的分布有很大的影响.宽度较小,高度较大的街谷结构内流场较复杂,污染物在其中比较不容易扩散.本文对不同街谷结构内流场和污染物浓度场的分布进行了对比分析,对城市规划设计、城市气候以及城市空气质量控制等领域具有重要意义.

Numerical Simulation of Flow Field and Pollution Concentration Field in Street Canyon Structures

From the three-dimensional scale, we simulate the flow field and the pollution concentration field of six different geometrical sizes street canyon structures. The Spalart-Allmaras turbulent model is used to simulate the flow field; and the convectiondiffusion model which couples with the flow field is used to simulate pollutant concentration field. The finite element method is used to discrete differential equation. The simula- ted result indicates that the street canyon structure geometrical size has very tremendous influence on the flow field and pollution concentration field＇s distribution. The street canyon sti＇ucture with smaller width and high- er height has the more complex flow field~ and the pollutant will be not easy to diffuse. We simulate and ana- lyze the flow field and pollutant concentration field＇s distribution of the street canyon structures with different geometrical sizes and in different positions. The result has great significance for the urban planning and designing, urban climate and city air quality controlling, etc.