arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1906.07375physics.flu-dyn
收藏

低质量阻尼涡激振动中有效阻力和升力的相动力学

Phase dynamics of effective drag and lift in vortex-induced vibration at low mass-damping

Efstathios Konstantinidis, Jisheng Zhao, David Lo Jacono, Justin Leontini, John Sheridan

摘要:

在这项工作中,我们研究了具有非常低的质量和阻尼值的弹性安装的圆柱体的涡激振动的动力学。我们使用两种方法来研究这个典型的问题:首先,我们计算的瞬时相位之间的圆柱体运动和流体强迫;第二,我们分解成总的水动力的阻力和升力分量,分别沿和垂直于,瞬时有效的迎角。我们专注于在大振幅响应范围内的相位动力学,包括初始,上,下分支的响应。横向力和位移之间的瞬时相位显示出重复的相位滑移,该相位滑移将上分支的后半部分中的恒定或连续漂移相位的周期分开。升力分量和位移之间的相位在整个大幅度范围内显示出强的相位锁定-平均相位随主频率线性变化-然而,该相位的调制在上分支的后半部分中最大。这些观察结果表明,大振幅响应动力学是由两个不同的极限环驱动的-一个是稳定的,在一个非常小的范围内的减少速度开始的上分支,另一个是由下分支。当两个极限环都不稳定时,它们之间的混沌振荡--上分支的大部分--就会发生。上分支和下分支之间的过渡以间歇性切换为标志,其中不同的状态以恒定的降低速度存在。这些不同的状态在升力和位移之间的阶段是明显的,说明了所采用的力分解的效用。

英文摘要:

In this work, we investigate the dynamics of vortex-induced vibration of an elastically mounted cylinder with very low values of mass and damping. We use two methods to investigate this canonical problem: first we calculate the instantaneous phase between the cylinder motion and the fluid forcing; second we decompose the total hydrodynamic force into drag and lift components that act along and normal to, respectively, the instantaneous effective angle of attack. We focus on the phase dynamics in the large-amplitude-response range, consisting of the initial, upper and lower branches of response. The instantaneous phase between the transverse force and displacement shows repeated phase slips separating periods of constant, or continuous-drifting, phase in the second half of the upper branch. The phase between the lift component and displacement shows strong phase locking throughout the large-amplitude range - the average phase varies linearly with the primary frequency - however the modulation of this phase is largest in the second half of the upper branch. These observations suggest that the large-amplitude-response dynamics is driven by two distinct limit cycles - one that is stable over a very small range of reduced velocity at the beginning of the upper branch, and another that consists of the lower branch. The chaotic oscillation between them - the majority of the upper branch - occurs when neither limit cycle is stable. The transition between the upper and lower branches is marked by intermittent switching with epochs of time where different states exist at a constant reduced velocity. These different states are clearly apparent in the phase between the lift and displacement, illustrating the utility of the force decomposition employed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑