论文标题
两个并排的圆形圆柱体之间的尾流相互作用不同
Wake interactions between two side-by-side circular cylinders with different sizes
论文作者
论文摘要
由于耦合唤醒之间的复杂相互作用，在两个并排的圆形圆柱体上的流动表现出引人注目的流动物理。但是，到目前为止，它们的相互干扰效应尚未以定量方式阐明。在本文中，我们通过在圆柱对中引入大小差异来在两个唤醒之间产生不匹配，从而可以区分一个尾流对另一个尾流的影响。根据两个圆柱体之间的尺寸和间隙比，耦合的尾流具有不同的动力学特征，包括准周期流，同步流和混乱的流动。通过对升力系数的高级光谱分析和流场的动态模式分解，我们揭示了准周期流的主要频率主要由两个与涡流脱落相关的两个主要频率组成，这是两个圆柱体的近唤醒。两种唤醒都将自己的频率强加于另一个频率，从而导致升力系数的跳动现象。两种唤醒之间的三合会相互作用会产生侧带频率，这些侧带频率与远处尾流中主要有效的模态结构相关联。从准周期性到同步的过渡主要由较大的气缸后面的涡流脱落，而较小的圆柱体锁的唤醒。这些结果揭示了对两个圆形圆柱体的耦合唤醒的新见解，并且主要是了解更多的一般唤醒交互问题。
Flows over two side-by-side circular cylinders exhibit fascinating flow physics due to complex interactions between the coupled wakes. However, their mutual interference effects have not been elucidated in a quantitative manner thus far. In this paper, we create a mismatch between the two wakes by introducing a size difference in the cylinder pair, such that the effects of one wake on the other can be distinguished. Depending on the size and gap ratios between the two cylinders, the coupled wake exhibits distinct dynamical features including the quasi-periodic flow, synchronized flow, and chaotic flow. Through advanced spectral analysis of lift coefficients and dynamic mode decomposition of the flow fields, we reveal that the quasi-periodic flows are mainly composed of two primary frequencies associated with vortex shedding in the near wakes of the two cylinders. Both wakes impose their own frequencies on the other, resulting in the beating phenomenon in the lift coefficients. The triad interactions between the two wakes generate the sideband frequencies, which are associated with modal structures that are mostly active in the far wake. The transition from quasi-periodicity to synchronization is dominated by the vortex shedding behind the larger cylinder, to which the wake of the smaller cylinder locks in. These results reveal new insights on the coupled wakes of two circular cylinders, and are pivotal for understanding more general wake interaction problems.
