摘要
弄清开缝钝体尾迹的拟序结构是认识其火焰稳定机理的基础。在雷诺数R e为470000条件下,采用RNGk-ε模型对通道内的开缝钝体尾迹进行数值模拟来分析大涡尺度的拟序结构。模拟结果显示,偏向一侧的中缝流将近尾分成主回流区和次回流区,主回流区的漩涡脱落激发扰动,引起近尾的绝对不稳定。并提出单涡突然置于两剪切层间的漩涡脱落机理来解释拟序结构不稳定特性。为了验证上述结论,在闭式风洞中采用激光粒子测速技术(P IV)对开缝钝体的尾迹进行了实验研究,其结果与数值分析较好地吻合。
To understand flame holding mechanism of a slotted bluff body based on the resotutton of its coherent structure in the wake. The wake over a slotted bluff body in a confined tunnel was investigated numerically by RNG k-ε model at Reynolds number of 470000, its coherent structure of large size vortex was analyzed. The near wake is divided by the gap flow into two zones called the primary recirculation zone and the secondary recirculation zone, the vortex shedding in the primary recirculation zone initiates disturbance which causes absolute instability in the near wake. To explain the physics of instability in the coherent structure, a vortex shedding mechanism that single vortex suddenly immerses between two shear layers was proposed. PIV measurements in a close wind tunnel were also carried out to confirm the observation from the numerical study. The evidence shows that the numerical results are in good agreement with the experiments.
出处
《计算力学学报》
EI
CAS
CSCD
北大核心
2006年第1期118-123,共6页
Chinese Journal of Computational Mechanics
关键词
钝体
尾迹
拟序结构
漩涡脱落
bluff body
wake
coherent structure
vortex shedding
