arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2201.05448physics.flu-dyn
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旋涡中的螺旋运动

Spirographic motion in a vortex

Sumithra Reddy Yerasi, Rama Govindarajan, Dario Vincenzi

摘要:

旋涡流中颗粒运动的研究主要集中在点状颗粒上,无论是惯性的还是自推进的。这个近似假设粒子周围的速度场是线性的。本文考虑二维定常涡中的无惯性刚性哑铃。虽然系统保持解析易处理,但粒子经历周围速度场的非线性。通过利用旋转对称的流动,我们减少了问题的二维动力系统,其不动点和周期轨道可以用来解释哑铃的运动。对于流体角速度随径向距离减小的所有涡流,哑铃的质心遵循围绕涡流中心的螺旋轨迹。这是由于径向上的周期性振荡与围绕中心的旋转相结合。轨迹的形状强烈地依赖于哑铃的初始位置和方向,但无论旋涡的形式如何,动力学性质都是相同的。如果流体的角速度不是单调的,那么螺旋运动就会因传输障碍的存在而改变,传输障碍的形状现在对涡旋的细节很敏感。

英文摘要:

Studies of particle motion in vortical flows have mainly focused on point-like particles, either inertial or self-propelled. This approximation assumes that the velocity field that surrounds the particle is linear. We consider an inertialess rigid dumbbell in a two-dimensional steady vortex. While the system remains analytically tractable, the particle experiences the nonlinearity of the surrounding velocity field. By exploiting the rotational symmetry of the flow, we reduce the problem to that of a two-dimensional dynamical system, whose fixed points and periodic orbits can be used to explain the motion of the dumbbell. For all vortices in which the fluid angular velocity decreases with radial distance, the center of mass of the dumbbell follows a spirographic trajectory around the vortex center. This results from a periodic oscillation in the radial direction combined with revolution around the center. The shape of the trajectory depends strongly on the initial position and orientation of the dumbbell, but the dynamics is qualitatively the same irrespective of the form of the vortex. If the fluid angular velocity is not monotonic, the spirographic motion is altered by the existence of transport barriers, whose shape is now sensitive to the details of the vortex.

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。

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