边界入流风场扰动对模拟城市大气扩散的影响

发布时间：2018-02-12 07:02

  本文关键词： 城市扩散 中性层结 CFD 边界条件 数值试验　出处：《中国环境科学》2017年09期 　论文类型：期刊论文

【摘要】：借助计算流体动力学(CFD)模式Fluent分析中性层结下边界入流风场(即风速和风向)扰动对地面点源释放情景下城市大气扩散过程的影响,其中边界入流条件以风速和湍流动能廓线的形式给出.研究发现CFD模式能够合理刻画实际城市中的特征流型(如涡旋,峡谷效应等),而且模拟的风速、风向和湍流动能均与观测数据吻合较好.敏感性试验结果表明,城区内的流场和湍流以及与之密切相关的污染物空间分布对边界入流风速和风向的扰动十分敏感.而这可能是造成已有研究中浓度模拟值与观测值不一致的主要原因之一.因此,在模拟城市大气扩散过程时应当考虑边界入流风场不确定性对模拟结果的影响.
[Abstract]:By using the computational fluid dynamics (CFD) model Fluent, the influence of the disturbance of the boundary inlet wind field (I. E. wind speed and wind direction) on the urban atmospheric diffusion process under the ground point source release scenario is analyzed. The boundary flow conditions are given in the form of wind speed and turbulent kinetic energy profile. It is found that the CFD model can reasonably describe the characteristic flow patterns (such as vortex, canyon effect, etc.) in the actual city, and the simulated wind speed. The wind direction and turbulent kinetic energy are in good agreement with the observed data. The flow field and turbulence in urban area and the spatial distribution of pollutants closely related to them are very sensitive to the disturbance of the wind speed and direction of the boundary flow, which may be the main cause of the inconsistency between the simulated and observed concentration values in previous studies. One of the reasons. The influence of boundary inlet wind field uncertainty on the simulation results should be considered in the simulation of urban atmospheric diffusion process.
【作者单位】： 兰州大学大气科学学院半干旱气候变化教育部重点实验室;中国科学院西北生态环境资源研究院寒旱区陆面过程与气候变化重点实验室;中国人民解放军93811部队;
【基金】：国家“973”计划项目(2011CB706903) 国家自然科学基金资助项目(41275019,41475009)
【分类号】：X169
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本文编号：1505051