MRI Measurement of Convective Motion in Vibrated Granular Bed

概要

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An NMR (Nuclear Magnetic Resonance) imaging technique was employed to visualize the convective motion in a horizontally vibrated granular bed. The size segregation phenomena are observed for a binary mixture of larger and smaller particles. Temporal progress of the size segregation was evaluated for three different combinations of binary mixture. The convective motion was clearly observed by MRI, that is, the smaller particles tended to fall down along the side wall, while the larger particles tended to rise through the central region. The convective motion is observed even in the plane perpendicular to the vibration direction as well as in the plane parallel to the vibration direction for all combinations of binary mixture. It was suggested that the size ratio of larger to smaller particles and of vessel to particle affected the segregation phenomena.