不同圆角率的方形断面斯特罗哈数的雷诺数效应研究

Reynolds number effect of Strouhal number of square prism with different rounded corner ratios

通过刚性模型测压风洞试验在均匀流场中测试了标准方形断面及圆角率为0.1、0.2、0.3和0.4的方形断面在不同风向角下、雷诺数Re=0.8×105~3.6×105范围内的表面风压。在获得气动力系数时程的基础上,通过分析升力系数功率谱在试验雷诺数范围内的变化,讨论了圆角率和风向角对斯特罗哈数雷诺数效应的影响规律。结果表明:在试验雷诺数范围内,各风向角下标准方形断面与圆角率为0.1的方形断面斯特罗哈数均基本不受雷诺数的影响;圆角率为0.2、0.3和0.4的方形断面斯特罗哈数分别在0°~2.5°、0°~7.5°和0°~12.5°的小风向角时对雷诺数比较敏感,出现了大幅突升现象,圆角率越大,对雷诺数敏感的风向角范围越大。

Wind pressure of standard square prism and square prism with four different rounded corner ratios were tested through rigid model pressure-measured wind tunnel tests in uniform wind filed.The Reynolds number Re ranged from 0.8×105 to 3.6×105.The rounded corner ratio was 0.1,0.2,0.3 and 0.4,respectively.On the basis of time histories of aerodynamic force coefficients,the variation of lift coefficient power spectrum in test Reynolds number range were analyzed.The influence of rounded corner ratio and wind direction on Reynolds number effect of Strouhal number were discussed.The results show that for standard square prism and square prism with rounded corner ratio 0.1,the Reynolds number effect of Strouhal number is very weak under different wind directions.For square prism with rounded corner ratio 0.2,0.3 and 0.4,the Reynolds number effect of Strouhal number is significant under small wind directions,corresponding to 0°-2.5°,0°-7.5°and 0°-12.5°,respectively.The Strouhal number increases dramatically under these small wind direction regions.The larger rounded corner ratio is,the larger the range of wind angle sensitive to Reynolds number is.