Brazil nut effect controlled by vibration velocity

When grains of different sizes are vibrated, the largest particle rises and separates. This Braizl nut effect has been studied for a long time. However, there has been no consensus on what parameters (eg., frequency, acceleration, velocity of vibration) characterize this phenomenon. However, recent studies [1-2] have shown the convection velocity can be governed only by the vibration velocity when continuous vibrations were applied. Recently, we have conducted an experiment using small particles and a large disk in a pseudo-two-dimensional cell and found the rising motion is always governed by the vibration velocity when continuous vibrations were given [3]. Here, we further confirm the BN effect is controlled by vibration velocity even under discontinuous vibration [4]. We find that the BN effect under discontinuous vibration is divided into two regimes and the final convection regime is clearly governed by vibration velocity. This suggests the segregation due to convection can be universally controlled by the vibration velocity.
[1] Hejmady, et al., Phys. Rev. E, 86 (2012) 050301(R).
[2] Yamada and Katsuragi, Planet. Space Sci. 100 (2014) 79.
[3] Then, Sekiguchi, and Okumura, Soft Matter 16 (2020) 8612.
[4] Umehara and Okumura, J. Phys. Soc. Jpn. 89 (2020) 013188.