摘要
该文实验研究了低Reynolds数情况下正交圆柱尾迹的空间动力学行为。研究涉及不同来流速度,不同圆柱间距工况下,几何中心层和剪切层上旋涡的空间演化特性。空间动力学行为分析主要基于自谱和互谱的空间演化,并涉及空间相位分析。结果显示:正交圆柱尾迹法向方向和展向方向的自谱演化不具有对称特性,分别表现为类单圆柱性和二次流现象;在正交圆柱中心附近,通过自谱图发现尾迹处存在旋涡的三次归并现象以及亚谐波的嵌入现象;通过互谱和空间相位分析,在Re=68和Re=103工况下发现波数匹配现象,并且其频带的中心恰为正交圆柱脱落主导频率;特别在Re=68工况下脱落主导频率和一阶亚谐波存在波数匹配现象,并且随着Re数增加,相位关联消失。
This experimental study was put emphasis on the spatial dynamical behaviors of two circular-cylinders forming a cross at low Reynolds number. It is involved in the vortices space evolution characteristics of the middle layer and the shear layer by the different flow speed and the different cylinder spacing conditions. The spatial dynamical behavior analysis is mainly based on self-spectrum and cross spectrum, involving spatial phase analysis. The results are obtained by the self-spectrum that the normal direction and the spanwise direction do not have the symmetry of the direction in the wake of two circular cylinders arranged perpendicular to each other; that one is the wake of the vortex being similar to the single-cylinder and another isthe secondary flow phenomenon. Near the center of structure the third mergence and embedding is found in the wake of the two circular cylinders by the self-spectrum picture. On the other hand, by the way of cross spectrum and the spatial phase analysis, the wave-number-matching phenomenon is found in the case of Re = 68 and Re = 103. And the wave-number-matching phenomenon only exists around the shedding-frequency. In the case of Re = 68, it is found that the shedding-frequency and the first sub-harmonic wave have the same wave-number, and with the increasing of the Reynolds number, the determinable spatial-phases disappeared.
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2013年第3期370-378,共9页
Chinese Journal of Hydrodynamics
基金
国家自然科学基金面上项目(10872051)~~
关键词
正交圆柱
自谱
互谱
波数
波速
two circular cylinders forming a cross
self-spectrum
cross spectrum
wave number
wave velocity
