高雷诺数顶盖驱动方腔流实验

为得到高雷诺数(1×105~1×106)条件下顶盖驱动方腔水流流场和速度分布,设计了边长为0.2 m和0.5 m的立方腔,并利用粒子图像测速技术(Particle Image Velocimetry,PIV)对方腔流流场进行测量,分析方腔流流场特性和边壁对流场影响规律。结果表明:雷诺数达到5×105时方腔流中主涡旋发生变形,雷诺数从5×105增大到1×106过程中,中间的初级涡旋(Primary eddy,PE)继续变形,并分裂成两个涡旋;随着雷诺数的增大,顺流次级涡旋(Downstream Secondary Eddy Region,DSE)区域面积缩小,雷诺数为5×105时DSE区域可看到成型的涡旋,当雷诺数为1×106时,DSE区域继续缩小,在同样条件下看不到成型的涡旋;雷诺数增大的过程中各边壁的边界层变薄,边壁对方腔流流场特性影响明显。

Experimental study on lid-driven cavity flow at high Reynolds number

Laboratory experiments have been conducted to study high Reynolds number (from 1×10⁵ to 1×10⁶), three-dimensional lid-driven cavity flows in two cavity dimensions: 0.2m×0.2m×0.2m and 0.5m×0.5m×0.5m. Particle Image Velocimetry (PIV) technical was applied to investigate the flow field and the effects of wall on the flow fields. Measured time-averaged streamlines show that the primary eddy starts to distort at Re=5×10⁵ and starts to breakup into two/three eddies at Re=1×10⁶. The region of Downstream Secondary Eddy (DSE) decreases as the Reynolds number increases. At Re=5×10⁵, a fully developed DSE can be seen clearly. But it is hard to see when Re=1×10⁶. The thickness of boundary layer becomes thinner and thinner as the Reynolds number increases. The measurements also show that the side boundary has a significant impact of the primary eddy.