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为了分析阻塞度和洞壁效应对大比例模型风洞试验结果精度的影响,通过制作缩尺比为1∶9的大比例尺流线型桥梁断面模型,安装到高速移动的汽车上,形成不同风速的自然风场。测量了不同车速下(即不同雷诺数)模型的表面压力,拟合了试验数据,研究了自然风作用下高雷诺数区的流线型断面的三分力系数的变化规律以及表面压力分布的特点,并将自然风场数据与风洞试验数据进行了对比。研究结果表明:阻塞度和洞壁效应将对大比例模型的雷诺数效应产生较大影响,其中,当Re<3×105时,随着雷诺数Re的增加,考虑阻塞度和洞壁效应影响的阻力系数呈不断减小的变化趋势,而不考虑其影响的阻力系数呈上升的变化趋势;阻塞度和洞壁效应使得升力系数数值变小,而升力矩系数数值却变大;阻塞度和洞壁效应不会改变模型表面最小压力点出现的位置,但是会使模型表面压力系数数值变小。
In order to analyze the influence of the obstruction and the effect of the tunnel wall on the accuracy of the large-scale wind tunnel test, a large scale streamlined bridge cross-section model with a scale ratio of 1: 9 was installed to a high-speed moving vehicle to form natural winds with different wind speeds Wind farm. The surface pressure of the model under different vehicle speeds (ie, different Reynolds number) was measured and the experimental data were fitted. The variation law of the third component coefficient and the characteristics of the surface pressure distribution of the streamlined section in high Reynolds number area under natural wind were studied. The wind field data and wind tunnel test data were compared. The results show that the obstruction and the effect of the wall will have a great influence on the Reynolds number effect of the large-scale model. When Re <3 × 105, the effect of the obstruction and the effect of the wall will be considered as the Reynolds number Re increases. The drag coefficient shows a trend of decreasing while the drag coefficient without considering the influence has a tendency of increasing. The coefficient of lift coefficient decreases while the coefficient of lift moment increases with the degree of blockage and the effect of the wall. The wall effect does not change the position of the point of minimum pressure on the surface of the model, but decreases the value of the surface pressure coefficient.