LES analysis on the temporal-spatial structures of gust wind over complex terrain by using the wind turbulence simulator.

利用风湍流模拟器对复杂地形阵风时空结构进行LES分析

• 批准号: 12450222
• 负责人: TAMURA Tetsuro
• 金额: $ 7.17万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450222/
• 关键词: wind turbulence; complex terrain; simulation; LES; SGS turbulence modeling; gust wind; temporal-spatial structures; atmospheric surface layer

In case that the terrain is sharp and complicated, we often encounter the extremely high wind generated as a result of large deformation or separation of wind flows over undulation of ground surface. This causes damage to buildings and structures, so it is important for its mitigation to clarify strong wind characteristics over a complex terrain and estimate amplification factors of the design wind velocity. However the estimation of strong wind has been thus far limited to a relatively simple configuration of terrain. Taking into consideration complexity of actual terrain, the numerical technique is very expecting to predict the terrain effect on wind flows, compared to the wind experimental technique which requires a lot of efforts to make a terrain model individually. For the establishment of structural safety for buildings and structures to strong wind, it is required to estimate the instantaneous gust maximum as well as the averaged velocity for wind because this kind of wind has very large fluctuations in time and space. This study developed the unsteady computational technique of LES(Large eddy simulation) in the generalized coordinate system as a numerical turbulence model appropriate to strong wind over complex terrain and investigated the temporal-spatial structures of gust wind in the atmospheric surface layer. Especially we bring into focus the turbulence characteristics in the oncoming wind flows or over various types of surface roughness, and their effects on the strong wind are discussed.

在地形尖锐复杂的情况下，我们经常会遇到由于地表起伏的大变形或气流分离而产生的极强的风。这会对建筑物和结构造成破坏，因此，弄清复杂地形上的强风特征并估计设计风速的放大系数对于减轻其影响非常重要。然而，到目前为止，对强风的估计仅限于相对简单的地形。考虑到实际地形的复杂性，数值模拟技术可以较好地预测地形对风的影响，而风实验技术则需要花费大量的精力来单独建立地形模型。由于强风在时间和空间上的波动非常大，为了建立建筑物和结构在强风作用下的结构安全性，需要估计瞬时阵风最大值和平均风速。本文发展了广义坐标系下大涡模拟的非定常计算技术，将其作为一种适用于复杂地形强风的数值湍流模式，研究了大气表层阵风的时空结构。重点讨论了迎面风流和不同表面粗糙度的湍流特性及其对强风的影响。