ABSTRACT
Therefore, our intuition suggests that the ball dynamics in a finite-size box remains poorly affected by a second wall, provided that the wall-plate distance L is larger than the vibration amplitude b. In fact, as demonstrated in the experiments below, the assumption of gravitational instability, where transient chaotic 3-d behavior of the ball occurs as the most probable dissipative situation at large time, is not realistic. On the contrary, the ball tends to behave quasi-instantaneously as a perfect regular particle in a 1-d vibrating cavity with translation motion parallel to the vibration direction. The gain is large enough to get a resonant behavior. This demonstrates a drastic reduction of the phase space dimension because of the second wall increases the dissipation, eliminating the rotation of the ball and freezing its transverse velocity-fluctuations, as will be shown below.
