大气边界层模拟的湍流相似

大气边界层的风洞模拟,是目前研究建筑物风载,污染质的大气扩散,以及解决某些环境科学和军事科学中大型课题的重要手段之一。在许多国家,风洞模拟已成为环境部门设计大型工程、林区、厂区和城区规划的主要依据。最初的大气边界层模拟装置,仅考虑形成一定的平均风速廓线,并未考虑到气流的湍流特性。微气象学的研究表明,大气的湍流特性是影响扩散的主要因素。特别是Monin和Obukhov通过大量实测资料提出大气表面层中的相似性理论,成为研究大气扩散的重要依据。从50年代开始,一些研究大气扩散和建筑物风载问题的长实验段风洞相继筹划和建立。其中较著名的有,美国科罗拉多州立大学的1.8米×1.8米×30米的回流式长实验段气 

SIMILARITY OF TURBULENT CHARACTERISTICS IN ATMOSPHERIC BOUNDARY LAYER SIMULATION

Similarity criteria of turbulent characteristics in atmospheric boundary layer (ABL) simulation are deduced, and advantages and disadvantages of various simulation techniques arc discussed. An 1/1000 neutral ABL model in a low speed wind tunnel with 2.25m diameter at Beijing University has been set up by 1/4 elliptic wedge vorticity generator method, and it provided a good approximation of turbulent characteristics in the flow field to field measurement data and results from wind tunnels with long testing section. Results of its applications in wind engineering and air pollution problems demonstrated, that similarity of turbulent characteristics in this model is satisfactory.