【摘要】 在风洞中正确模拟大气边界层的流动特性是风工程风洞试验结果可信的必要条件,本次试验研究的目的是在短试验段的航空风洞中建立大比例的大气边界层模拟流场。通过适当的方式延长1.4m×1.4m航空风洞的试验段长度,并利用尖塔、粗糙元等边界层发生装置,在该风洞中建立了边界层流场,测量了流场的平均风速剖面、湍流强度剖面、脉动风速的自相关系数、风谱等参数,讨论了湍流积分尺度的处理和大气边界层几何模拟比例的确定,用谱拟合法和自相关系数积分法求出了湍流积分尺度。结果分析表明:试验所得流场是合理的大气边界层模拟流场,其平均风速剖面幂指数α=0.3,大气边界层模拟比例为1∶500,为后续的建筑物模型动态风荷载试验提供了前提条件。更多还原

【Abstract】 A correct simulation of the atmosphere boundary layer in wind tunnel is an essential condition of experimental investigations in wind engineering. A large geometric scale simulation flow field of the atmosphere boundary layer was established in an nautical wind tunnel with short test section. The simulation test of the atmospheric boundary layer was performed in a 1.4m×1.4m aeronautical wind tunnel by properly extending the length of the test section and by using some spires and roughness elements. In the test a boundary layer field was established. The mean velocity profile, the turbulence intensity profile, the autocorrelation coefficient of fluctuation wind velocity and the fluctuation wind spectra were all measured. Meanwhile, the determination of the turbulence integral length scale and the geometric simulation scale in the model field were discussed. The turbulence integral length scale was obtained by the spectra-fitting method and autocorrelation coefficient integration respectively. The test results show that the model field is a reasonable simulation of a atmospheric boundary layer with mean velocity profile exponent α=0.3, and geometric scale 1∶500. The results of the simulation field have reference meanings for the model test of dynamic wind loads on buildings aftertime.更多还原