A New Parametrization of Mixing Length in an Urban Canopy Derived from a Large-Eddy Simulation Database for Tokyo
A New Parametrization of Mixing Length in an Urban Canopy Derived from a Large-Eddy Simulation Database for Tokyo
复制标题
来自东京大涡模拟数据库的城市冠层混合长度的新参数化
DOI：
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发表时间：
2015
影响因子：
4.3
通讯作者：
M. Kanda
中科院分区：
文献类型：
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作者：
H. Kondo;A. Inagaki;M. Kanda
城市冠层中的平均水平风速主要由建筑物阻力引起的气流减速和冠层动量通量梯度引起的气流加速之间的平衡决定。为了表达动量在城市冠层中的传输，混合长度通常用于计算扩散率。针对一维多层城市冠层模式（UCM），提出了一种新的混合长度参数化方法。大涡模拟的数据库，使用实际的城市形态东京用于此参数化。导出的混合长度被描述为无量纲高度的q次方的函数，其中q <1 q <1。$$q$$q值和函数常数也取决于冠层高度的选择。混合长度剖面与研究区建筑物的平均平面面积指数密切相关。使用东京混合长度的新参数化重新计算平均水平风速略微改善了多层UCM结果。
Average horizontal wind velocity in an urban canopy is mainly determined by a balance between flow deceleration caused by the drag force of buildings and flow acceleration from the momentum flux gradient in the canopy. To express the transport of momentum in an urban canopy, mixing length is often used to calculate diffusivity there. A new parametrization for mixing length is introduced for a one-dimensional multilayer urban canopy model (UCM). A database from large-eddy simulations using actual urban morphology for Tokyo is used for this parametrization. The derived mixing length is described as a function of the non-dimensional height raised to the power of $$q$$q, where $$q < 1$$q<1. The $$q$$q value and constants of the function also depend on the selection of canopy height. The mixing length profile is closely related to that of the average plane area index of the buildings in the study area. Recalculation of mean horizontal wind velocity using the new parametrization of mixing length for Tokyo slightly improved the multilayer UCM results.
影响因子：
5
作者：
Letzel, Marcus Oliver;Krane, Martina;Raasch, Siegfried
通讯作者：
Raasch, Siegfried