LES Model for Wind Gusts over Urban Areas Represented by Buildings and Vegetations and Its Application to the Sophisticated Wind-Resistant Design

正确评价100 ~ 200 m海拔高度区域的风特性，是实现城市建筑结构风害缓解的重要手段。然而，地面表面覆盖着各种物体，如形状复杂的建筑物和多种植被，接近地面的空间是不均匀的。特别是在城市地区，中高层建筑密集，在几十米到一百米的高度范围内，空间面貌变化很大。本研究基于近年来CFD（计算流体力学）技术的快速发展，利用本项目工作人员开发的计算代码，构建了以城市各建筑物在地面上的实际形状直接表示的数值模型，可以高精度地预测强风湍流结构。为了阐明强风阵风的结构及其波动特征受地表粗糙度及其形状或波动的影响，进行了大涡模拟。利用研究结果和获得的信息，实现了建筑物和结构在强风作用下的结构安全，并进行了复杂的抗风设计。

In order to realize the wind hazard mitigation for buildings and structures in urban area, it is important to evaluate correctly the wind characteristics in the altitude region at 100 to 200 m. However the ground surface is covered by various objects such as buildings with complicated shape and many sorts of vegetations, and the space close to the ground is not uniform. Especially, in urban area middle- and high- rise buildings are densely built, so that spatial aspect varies very much in the altitude range of tens meters to a hundred meters. In this research, based on the recent rapid development of CFD (Computational Fluid Dynamics) technique, we utilize the computational code developed by the staff of this project for constructing the numerical model which is directly represented by the actual shape of each building on the ground surface in urban area and can predict the turbulence structures of strong wind with high accuracy. The large eddy simulation (LES) is carried out, in order to clarify the structures of strong wind gust and its fluctuation characteristics influenced by the roughness conditions of ground surface and its shape or undulation. Also, utilizing the results and the information obtained, the structural safety of buildings and structures against strong wind is realized and the sophistication of the wind-resistant design is performed.