典型山地风场三维效应大涡模拟研究  

Study on Three Dimensional Effects of Typical Mountain Wind Filed by Large Eddy Simulation

作　　者：郑德乾[1] 卞莉 李亮 方平治[2] Zheng Deqian;Bian Li;Li Liang;Fang Pingzhi

机构地区：[1]河南工业大学土木工程学院,河南郑州450001 [2]中国气象局上海台风研究所,上海200030

出　　处：《重庆建筑》2023年第10期13-17,共5页Chongqing Architecture

基　　金：国家重点研发计划(2018YFB1501104)。

摘　　要：山地风场研究对于山区建筑物以及构筑物抗风设计至关重要。以余弦型山丘模型为对象,采用大涡模拟方法,研究典型山地风场三维效应。在通过二维模型大涡模拟与文献试验结果对比的基础上,进行三维模型大涡模拟,详细比较两种模型风场特性,时均瞬态流场演化规律;将数值模拟所得地形加速效应与不同国家规范进行对比。结果表明:该文数值方法可有效模拟山地风场平均脉动风特性;相同坡度下,二维和三维模型平均脉动风场变化规律总体相同;地形加速效应在迎风面变化规律基本相同;二维模型加速效应在迎风面和山顶位置偏大,背风面靠近地面处明显小于三维模型;两种模型均在山顶位置发生流动分离;背风面两模型均有复杂漩涡脱落及再附现象,其中二维模型以大尺度涡为主,三维模型以小尺度涡为主,这是由于三维模型顶部脱落漩涡受到山体两侧绕流脱落旋涡撞击和混合所致,使得三维模型在背风面漩涡脱落频率更丰富,能量更为分散,涡脱轨迹更为复杂。In the wind resistance design for buildings and structures in mountainous regions,it is of great importance to accurately simulate the wind field.Using the cosine hill model as the object,the large eddy simulation method is adopted to study the three-dimensional effects of wind fields in typical mountainous regions.Based on the comparison of results obtained through large eddy simulation with two-dimensional models and the experimental results in literature,large eddy simulation with three-dimensional models was conducted to carefully compare the wind field effects between the two models and get the evolution law of the temporal transient flow field;and the terrain acceleration effects obtained from numerical simulation were compared with different national standards.The results showed that the present numerical method can effectively simulate the characteristics of the mean and turbulence terrain wind field.Variations of the mean and fluctuating wind field are basically the same under the same slope.The simulated topographical acceleration of the two models present almost the same trend in the windward,except that the topographical acceleration of the 2D model is larger at the windward and hilltop position.In the leeward surface near the ground,the topographical acceleration of the 2D model gets significantly smaller than that of the 3D model.Flow separations are observed on the top position for both the two models.In the leeward region,there exist complex phenomenon of vortex shedding and reattachment around the two models.Large-scale vortices dominate the 2D model,and small-scale vortices dominate the 3D model.This is because the vortices shedding at the top of the 3D model are hit and mixed by those shedding on both sides of the mountain,making the frequency of vortex shedding on the leeward side of the 3D model greater,energy more dispersed,and vortex-shedding trajectory more complex.

关 键 词：大涡模拟 典型山地 地形风场 流场机理 三维效应 

分 类 号：TU312.1[建筑科学—结构工程]