摘要
林木几何形态特征复杂,且较为轻柔,在风荷载作用下会发生变形和振动,空气动力学效应复杂。针对如何通过风洞试验尽可能真实地模拟防护林在实际风场中的防风效应问题,通过梳理已有国内外相关文献,从模型设计、来流模拟和测试技术3个方面对灌木和乔木防护林防风效应风洞模拟试验的研究进展进行综述。结果表明:防护林风洞试验模型几何缩尺比的确定要综合考虑林木和风洞截面的尺寸,阻塞比一般应控制在5%以下;考虑到林木在风荷载作用下产生的变形和振动会进一步影响周围流场,模型设计时除了要考虑几何相似,还要加强对动力相似的考虑;在防护林风洞试验来流模拟及周围风速测定中,在平均风速的基础上,应加强对脉动风速统计特性的考虑;当采用天平测定林木气动力系数时,应结合林木风洞模型自身频率确定采样频率,避免2个频率过于接近造成结果失真。
The geometrical morphological characteristics of shelterbelt are complex and relatively flexible.The deformation and vibration will occur under the wind load,and the aerodynamic effects of shelterbelt are quite complex.How to simulate the windbreak effect of shelterbelt under the actual wind field as realistically as possible in the wind tunnels is particularly important.In view of this,this study summarizes the pertinent literature published at home and abroad,and reviews the progress research of windbreak effects of shrub and tree shelterbelt from the aspects of model design,approaching flow simulation and testing technology in the wind-tunnel simulation tests.The results show that:The determination of geometric scale of shelterbelt model should consider the size of shelterbelt and wind tunnel section,and the blockage ratio should be generally smaller than 5%;Considering that the deformation and vibration of trees under wind load will further affect the surrounding flow field,the dynamic similarity should be paid special attention to in addition to geometric similarity in model design;On the basis of mean wind speed,the consideration of statistical characteristics of fluctuating wind speed should be strengthened in the approaching flow simulation and wind speed measurement in the wind tunnel testing of shelterbelt;When the balance is used to determine the aerodynamic coefficients of shelterbelt,the sampling frequency should be determined according to the frequency of the model itself,so as to avoid the result distortion caused by the two frequencies being too close.
作者
王京学
王秀龙
冀晓东
李丹煜
赵国烨
孙禹枫
WANG Jingxue;WANG Xiulong;JI Xiaodong;LI Danyu;ZHAO Guoye;SUN Yufeng(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;State Grid Corporation of China,Beijing 100031,China;China Electric Power Research Institute,Beijing 100192,China)
出处
《中国农业大学学报》
CAS
CSCD
北大核心
2023年第12期162-176,共15页
Journal of China Agricultural University
基金
国家电网有限公司科技项目(5200-202318147A-1-1-ZN)。
关键词
防护林
风洞试验
相似条件
模型设计
来流模拟
测试技术
shelterbelt
wind tunnel test
similarity condition
model design
approaching flow simulation
testing technology
