串列方形钝体构筑物绕流的数值分析

采用二阶CBS有限元法对雷诺数Re=100时不同间距的串列方形钝体构筑物的绕流进行数值研究，分析了间距比s（构筑物中心距离与构筑物宽度d之比）对流场的影响，以及平均阻力系数、阻力系数均方根、升力系数均方根、斯特劳哈尔数和压力系数随间距比变化的情况. 结果表明：间距比对串列方形钝体构筑物的流场影响显著；当2个方形构筑物为串列情形时，可有效降低流体阻力；当临界间距比在4.50~4.75时，其各项力学性能指标将发生跳跃；由于上游构筑物尾流的影响，下游构筑物的升力系数均方根总大于上游构筑物而表现出更强的脉动性，且2个构筑物表面压力分布的差异显著.

Numerical Analysis of Flow Past Two Bluff Bodies with Square-Section in Tandem Arrangement

The flow past two tandem square-section bluff bodies with various spacing ratios was investigated numerically by using a second-order CBS finite element algorithm.The study mainly focuses on the effect of spacing ratios(ratio of center-to-center distance to width of bluff body) on the flow characteristics at a Reynolds number of 100.The mean drag coefficient and the root-mean-square drag and lift coefficients,the Strouhal number as well as the pressure coefficient are plotted as a function of the spacing ratio.The results reveal that spacing ratio has a great impact on the flow characteristics and the critical spacing ratio range is identified between 4.50 and 4.75,since the mean and root-mean-square force coefficients jump suddenly in this spacing ratio interval.When two bluff bodies with square-section are placed in tandem,the mean drag coefficient can be reduced effectively.The results also show that the root-mean-square lift coefficient of the downstream bluff body is always greater than that of upstream bluff body due to the wake interference.A significant difference of surface pressure coefficient distribution can also be observed.