Rolling and no-slip bouncing in cylinders

Figure 1.  No-slip billiard system between two parallel plates under gravity have bounded orbits in all dimensions. Far left: a simple periodic orbit with gravity turned off. Orbits shown from left to right are under the influence of increasing force

Figure 2.  Conditions for a transversal period $ 2 $ orbit in dimension $ 3 $. The projection to $ \mathbb{R}^2 $ of the velocity $ u $ of the center of mass and the angular velocity $ \dot{\theta} $ are related by $ |\dot{\theta}| = (m r/\mathcal{I})|u\sin\phi| $, where $ m $ is the projected disc's mass, $ r $ is its radius, and $ \mathcal{I} $ is its moment of inertia for the projected (or marginal) mass distribution

Figure 3.  Cross-section of the stadium cylinder and the rolling sphere

Figure 4.  Height of center of mass of rolling particle in a cylinder with stadium cross-section

Figure 6.  When the transversal rolling impact condition does not hold (see Definition 2.8), the particle acquires an overall acceleration downward. The apparent increase in thickness of the height function graph and of the particle's path is due to a small scale vertical zig-zag motion of increasing amplitude. See also Figure 8

Figure 8.  Near grazing paths of no-slip billiard particle. On the left-hand side, the transversal rolling impact condition holds for the initial bounce, but on the right-hand side a small deviation of this condition is introduced. Notice the characteristic zig-zag nature of the curve and that it does not return all the way to the initial height. The starting center of mass position is indicated by the small black dot

Figure 5.  Comparison of the height functions for the rolling motion in a circular cylinder under a constant downward force (solid line) and the corresponding no-slip billiard motion satisfying the transverse rolling impact condition (small circles). Initial conditions are chosen so that the two processes rotate around the cylinder at the same rate

Figure 7.  These graphs correspond to a fixed initial transversal rolling defect $ -r\omega\cdot e/u\cdot\tau_a = 1.15. $ (When the transversal rolling impact initial condition holds, this value is $ 1 $.) Here $ \omega\cdot e $ is the longitudinal component of the initial angular velocity vector and $ u\cdot \tau_a $ is the tangential (to the boundary of the billiard domain) component of the center of mass velocity. As the intercollision flight becomes shorter and motion grazes the cylinder more and more closely, the height function becomes smooth but the falling rate remains essentially unchanged

Figure 9.  Notation for the proof of Corollary 1

Figure 10.  Cross-sectional projection of initial velocity $ \bar{u}_0 $ and definition of $ \theta $ and $ \delta $

Figure 11.  Transition from regular to chaotic motion. The moving particle begins from the middle of the lower flat side with linear velocity pointing up and a small angular velocity that causes it to move right after the first collision with the upper flat side. For small values of the angular velocity trajectories never touch the curved sides of the boundary, and the motion along the axis of the cylinder is bounded. If the initial angular velocity is large enough, trajectories move beyond the ends of the flat sides and eventually becomes unstable

Figure 12.  Transition from regular to chaotic motion for the transverse dynamics of the stadium cylinder no-slip billiard system, as viewed in the velocity phase portrait. The full velocity space is a disc of radius $ 1 $ as shown in the far right. Initial conditions for the depicted orbits roughly compare to those of Figure 11

Figure 13.  Height function for the stadium cylinder for a trajectory in the chaotic regime, corresponding to the short orbit segment on the right of Figure 11 and of Figure 12. To give a sense of the scales involved, the diameter of the stadium is $ 8 $ and velocities are of order $ 1 $. The number of time steps is $ 4\times 10^4 $