论文标题
高速圆柱尾流中的曲卢哈尔数字通用性
Strouhal number universality in high-speed cylinder wake flows
论文作者
论文摘要
在雷诺数范围$ 2.3 \ times10^5 $至$ 5 \ times10^5 $上，在2D圆形圆柱体的近醒区域的流动振荡进行了实验研究。振荡频率是通过高速Schlieren数据的光谱正交分解获得的。发现基于近探针层的长度的曲线数表现出普遍的行为。这证实了最近文献中马赫4的实验发现，此外，普遍的行为也被认为是关于马赫数的。圆柱后表面的流动分离点处的时间分辨压力测量表明，相干振荡活动发生在两个流动的两个统计对称半径之间的相位差为$π$弧度。高速流动动力学的这一方面与其低速对应物相同，即圆柱体在不可压缩流中唤醒的规范问题。
Flow oscillations in the near-wake region of a 2D circular cylinder are experimentally investigated at Mach 6 over the Reynolds number range $2.3\times10^5$ to $5\times10^5$. The oscillation frequency is obtained by spectral proper orthogonal decomposition of high-speed schlieren data. The Strouhal number based on the length of the near-wake shear layers is found to exhibit universal behavior. This corroborates experimental findings at Mach 4 from recent literature, and further, the universal behavior is also seen to hold with respect to Mach number. Time-resolved pressure measurements at the flow separation points on the cylinder aft surface show that coherent oscillatory activity occurs with a phase difference of $π$ radians between the two statistically-symmetric halves of the flow. This aspect of the flow dynamics at high speeds is in common with its low-speed counterpart, i.e. the canonical problem of cylinder wake in an incompressible flow.
