Surface instabilities in vertically vibrated suspensions of various powders dispersed in silicone oil are investigated in quasi-two-dimensional (2D) and quasi-one-dimensional (1D) systems. As vibration acceleration exceeded a critical value, the flat surface became unstable against a finite-amplitude perturbation. We found an expanding hole or viscous fingerlike pattern in the quasi-2D system and segregation between dried and wet areas in the quasi-1D system. We show that these instabilities are accompanied by convectionlike flow at their rim and in the quasi-1D system, the height of the convectionlike flow can be scaled by acceleration, vibration frequency, diameter of the dispersed powder, mean density of the suspension, and viscosity of silicone oil. We propose a simple model that accounts for the scaling and concentric motion of the convectionlike flow.
|ジャーナル||Physical Review E - Statistical, Nonlinear, and Soft Matter Physics|
|出版ステータス||出版済み - 6月 16 2009|
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