Laminar flow instability in a rectangular channel with a cylindrical core
Laminar flow instability in a rectangular channel with a cylindrical core
复制标题
DOI：
10.1063/1.2194968
复制
发表时间：
2006-04
影响因子：
4.6
通讯作者：
A. Gosset;S. Tavoularis
中科院分区：
文献类型：
--
作者：
A. Gosset;S. Tavoularis
在含有圆柱杆的矩形通道中的层流实验表明，流动不稳定的形式是在杆与通道壁之间的间隙处有微弱的脉动。当雷诺数达到临界值时发生不稳定，该临界值随着间隙的减小而增大。随着雷诺数的增加，脉动变得更强并发展，首先形成发夹形状，然后形成准周期层流涡旋，它们在缝隙的两侧交替。最终，流动变得湍急，尽管保留了准周期的涡旋结构。在本实验范围内，脉动的Strouhal数随雷诺数的增加而增大。在前人对壁面边界流的低速条纹不稳定性和向湍流转变的分析的基础上，讨论了不稳定过程。
Experiments in laminar flow in a rectangular channel containing a cylindrical rod have revealed a flow instability in the form of weak pulsations across the gap between the rod and the channel wall. The instability occurs when the Reynolds number reaches a critical value, which increases as the gap diminishes. As the Reynolds number is increased, the pulsations become stronger and develop, first into hairpin-shaped patterns, then into quasiperiodic laminar vortices, which alternate on either side of the gap. Eventually, the flow becomes turbulent, albeit preserving a quasiperiodic vortical structure. Within the present experimental range, the Strouhal number of the pulsations increases with increasing Reynolds number. The instability process is discussed in the context of previous analyses of low-speed streak instability of wall-bounded flows and transition to turbulence.