类方柱绕流的雷诺数效应

Reynolds Number Effects of Flow Around Square-Like Cylinders

摘要:

采用计算流体动力学方法，系统研究了弧边曲率B/K = 0~1.77、圆角半径R/B = 1/7、雷诺数 Re = 20~ 22 000的类方柱绕流（B为名义边长、K为弧边半径、R为圆角半径）；分析了不同弧边曲率条件下，弧边和圆角组合气动外形的整体气动参数、表面压力分布、绕流场形态及流场参数的雷诺数效应。Re < 1 000时柱体具有相对一致的气动力雷诺数效应；Re ≥ 1 000时，小弧边曲率B/K = 0~0.80柱的气动参数雷诺数效应同圆角方柱接近，而大弧边曲率B/K = 1.00~1.54柱的气动参数雷诺数效应相对不明显；Re ≥ 10 000时，小弧边曲率柱和圆柱的平均和脉动气动力较强，而大弧边曲率柱的气动力较弱。B/K = 1.00时在各个雷诺数均具有较好的气动性能。随雷诺数的增加，小弧边曲率柱的流动分离点从后角点逐渐移动到前角点，而大弧边曲率柱和圆柱的流动分离点则从后角点逐渐移动到弧边中间位置。

Abstract:

Using the computational fluid dynamics method， a systematic study was conducted on the flow around square-like cylinders with round-side curvature ratios B/K = 0–1.77， a round-corner radius R/B = 1/7， and Reynolds number Re = 20–22 000 （where B is the nominal side length， K is the radius of the round sides， and R is the corner radius）. Under various side curvature conditions， the effects of Reynolds number on overall aerodynamic parameters， surface pressure distribution， flow field pattern， and flow parameters were analyzed， considering the combined influence of round sides and corners. For Re <1 000， the cylinders have a relatively consistent Reynolds number effect on aerodynamic forces. When Re ≥ 1 000， the Reynolds number effect on the aerodynamic parameters of cylinders with small round-side curvature （B/K=0–0.80） is similar to that of rounded square cylinders， while the effect on cylinders with large round-side curvature （B/K= 1.00–1.54） is relatively less pronounced. When Re ≥ 10 000， cylinders with small round-side curvature and circular cylinders experience relatively strong average and fluctuating aerodynamic forces， while cylinder with large round-side curvature show weaker aerodynamic forces. When B/K=1.00， the cylinder has good aerodynamic performance across all Reynolds numbers. as Reynolds number increases， the flow separation points of cylinders with small round-side curvature gradually shift from the rear corners to the front corners， while for cylinder with large round-side curvature and circular cylinders， the separation points gradually move from the rear corners toward the middle of the rounded sides.