A self-consistent model for the saturation dynamics of the vortex shedding around the mean flow in the unstable cylinder wake
A self-consistent model for the saturation dynamics of the vortex shedding around the mean flow in the unstable cylinder wake
复制标题
不稳定圆柱尾流中平均流涡脱落饱和动力学的自洽模型
DOI：
10.1063/1.4926443
复制
发表时间：
2015
影响因子：
4.6
通讯作者：
F. Gallaire
中科院分区：
文献类型：
--
作者：
V. Mantič;Cristóbal Arratia;F. Gallaire
超临界不稳定性导致圆柱尾迹中的Benard-von Karman涡列是超临界Hopf分叉的一个著名例子：定常解变为线性不稳定并饱和到周期极限环。然而，一个简化的物理公式准确预测的饱和过程的过渡动力学是缺乏的。在我们以前的工作的基础上，我们在这里提出了一个简单的自洽模型，提供了一个清晰的描述的饱和机制，在准稳态的方式通过耦合的瞬时平均流与其最不稳定的本征模和其瞬时振幅通过雷诺应力。该系统被耦合为不同的振荡幅度，提供了一个瞬时平均流量的等效时间的函数。一个瞬态的物理图片描述，其中谐波扰动增长和变化的幅度，频率和结构，由于雷诺应力强迫的平均流量的修改…
The supercritical instability leading to the Benard-von Karman vortex street in a cylinder wake is a well known example of supercritical Hopf bifurcation: the steady solution becomes linearly unstable and saturates into a periodic limit cycle. Nonetheless, a simplified physical formulation accurately predicting the transition dynamics of the saturation process is lacking. Building upon our previous work, we present here a simple self-consistent model that provides a clear description of the saturation mechanism in a quasi-steady manner by means of coupling the instantaneous mean flow with its most unstable eigenmode and its instantaneous amplitude through the Reynolds stress. The system is coupled for different oscillation amplitudes, providing an instantaneous mean flow as function of an equivalent time. A transient physical picture is described, wherein a harmonic perturbation grows and changes in amplitude, frequency, and structure due to the modification of the mean flow by the Reynolds stress forcing...