CFD SIMULATION STUDY OF INFLUENCE OF THERMAL EFFECT OF COASTAL URBAN BUILT-UP AREAS ON LOCAL CIRCULATION
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摘要: 基于计算流体力学(CFD)模拟开展了一系列理想数值试验, 分析了城市建成区的热力作用对局地环流的影响, 模拟结果表明: 在没有背景风的情况下, 城市热岛效应可破坏海陆环流的固有转换模式, 使近地面风场总是在城市建成区上空辐合; 在有微弱背景风的情况下, 热岛效应也会导致近地层风场出现线型辐合。而城市上空总是容易出现辐合风场, 可部分解释城市局地高污染带形成的物理机制。Abstract: Based on computational fluid dynamics (CFD) simulation, a series of ideal numerical experiments are carried out to analyze the influence of thermal effect of urban built-up area on local circulation. The results show that in the case of no background wind, urban heat island effect can destroy the inherent conversion mode of land-sea circulation and make wind field converge over urban built-up area; while in the case of weak background wind, urban heat island effect will also lead to line-shaped convergence in the wind field of surface layer. The analysis shows that the existence of urban built-up area will always cause the convergence of wind field near ground, which can partly explain the physical mechanism of local-scale heavy pollution.
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Key words:
- urban heat island /
- land sea circulation /
- local-scale circulation /
- local-scale pollution /
- CFD
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图 3 水槽实验的数值版本
a.复制于文献[16]; b.本研究重复验证试验,单位:m/s。
表 1 敏感性数值实验条件设置
序号 时段 背景风速/(m/s) 陆表温度/K 海表温度/K 空气温度/K 有无城市 城市地表温度/K 1 白天 0 318.15 298.15 300.00 有 320.00 2 夜晚 0 283.15 295.15 292.00 有 298.15 3 白天 0 318.15 298.15 300.00 无 - 4 夜晚 0 283.15 295.15 292.00 无 - 5 夜晚 1.0 283.15 295.15 292.00 有 298.15 -
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