低雷诺数串列双开缝圆柱绕流流场的特性研究

摘要

本文通过数值方法研究了层流串联双圆柱绕流中开缝的影响.通过改变圆柱间的中心间距以及开缝的倾斜角,揭示了流场结构、圆柱升力、阻力以及旋涡脱落的变化趋势,发现存在三种流态,它们间的相互转换可由阻力和升力的急剧变化体现.沿来流方向非对称的开缝对圆柱间的滞止区有干扰作用,而顺流的开缝则通过对滞止区的稳定作用将两个圆柱"联系"起来构成一个延展的钝体,该作用在较长圆柱间距下依然有效.以上干扰和稳定作用又影响流态间的转换.旋涡脱落也深受不同开缝和圆柱间距的影响.%This study investigated numerically the characteristics of laminar flow around two identical circular cylinders placed in tandem, with slits of the same width through their respective axis. The center to center distance between the cylinders and the slit orientation were varied to study their effects on the flow structure, lift and drag, and vortex shedding characteristics. It was found that three flow regimes could be distinguished, the transitions between which could be indicated by the sudden changes in drag and lift. Asymmetrically, configured slits destabilized the stagnant region between cylinders; whereas in-line slits connect the two cylinders to act as a single elongated bluff body, even at large cylinder separation, by stabilizing the stagnant region in between. These in turn strongly modified the transition between flow regimes. Vortex shedding was also strongly influenced by both slit configuration and cylinder separation.