钝体冷态流场的PIV实验研究

The PIV experimental investigation on cold-state wake behind bluff-body

运用PIV技术在风洞中分别对5种不同形式的钝体:标准钝体、三角形钝体、流线形钝体、带通道钝体及非流线形钝体在冷态工作环境、不同缝宽下,获取了钝体后的速度分布.对比了5种不同钝体在不同缝宽下回流区长度的变化,认为随开度增大,在回流区结构不遭到破坏的前提下,回流区长度加大.同等条件下,非流线形钝体有最大的回流区长度;通过对尾迹区域的平均湍流动能的分析,认为平均湍流动能的强度随缝开度加大开始减弱,湍流强度最大的区域逐渐后移,最终往回流区的上下边界发展.通过对钝体后的尾迹结构和流动特性进行分析,为热态实验奠定了基础.

A method of PIV technology was applied to measure the velocimetry field behind five kinds of bluff-bodies, including means standard-type bluff-body; tri-angle-type ; streamline-type ; tunnel-type and non-streamline type, in wind tunnel-type ones under cold state by changing their gaps, and the lengths of recirculating-zone of these bluff-bodies with different gaps were compared. It was seen that if the structure of recirculating-zone had not been destroyed, the lengths of recirculating-zone would increase with the increase of the gaps and the non-streamline-type bluff-body had the longest recirculating-zone among the five bluff-bodies. Another conclusion from analyzing the average turbulence energy in wake zone is that the intensity of the average turbulence energy was weakened with the increase of the gaps; in the end the zone with the biggest intensity would move backward and expanded to top and bottom boundaries of recirculating-zone. The structure of flow and the characteristics of flow behind all these five bluff-bodies were analyzed and a new basis for succulent hot experiment was given.