Halev Avishai, Harris Daniel M
Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Chaos. 2018 Sep;28(9):096103. doi: 10.1063/1.5023397.
We present an investigation of a partially elastic ball bouncing on a vertically vibrated sinusoidal surface. Following the work of McBennett and Harris [Chaos , 093105 (2016)], we begin by demonstrating that simple periodic vertical bouncing at a local minimum of the surface becomes unstable when the local curvature exceeds a critical value. The resulting instability gives rise to a period doubling cascade and results in persistent horizontal motion of the ball. Following this transition to horizontal motion, periodic "walking" states-where the ball bounces one wavelength over each vibration cycle-are possible and manifest for a range of parameters. Furthermore, we show that net horizontal motion in a preferred direction can be induced by breaking the left-right symmetry of the periodic topography.
我们展示了对一个在垂直振动的正弦表面上弹跳的部分弹性球的研究。遵循麦克贝内特和哈里斯的工作[《混沌》,093105(2016)],我们首先证明,当表面的局部曲率超过临界值时,在表面局部最小值处的简单周期性垂直弹跳会变得不稳定。由此产生的不稳定性会导致倍周期分岔,并导致球持续的水平运动。在向水平运动转变之后,周期性的“行走”状态——球在每个振动周期内弹跳一个波长——是可能的,并且在一系列参数下会表现出来。此外,我们表明,通过打破周期性地形的左右对称性,可以诱导球在一个优选方向上的净水平运动。