Universal stability curve for pattern formation in pulsed gas-solid fluidized beds of sandlike particles
Universal stability curve for pattern formation in pulsed gas-solid fluidized beds of sandlike particles
复制标题
砂状颗粒脉冲气固流化床中图案形成的通用稳定性曲线
DOI：
10.1103/physrevfluids.3.034303
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
M. Coppens
中科院分区：
文献类型：
--
作者：
L. de Martín;Coen P. Ottevanger;J. R. van Ommen;M. Coppens
颗粒层可以形成规则的图案，比如正方形、条纹和六边形，
A granular layer can form regular patterns, such as squares, stripes, and hexagons,
when it is fluidized with a pulsating gas flow. These structures are reminiscent of the
well-known patterns found in granular layers excited through vibration, but, contrarily to
them, they have been hardly explored since they were first discovered. In this work, we
investigate experimentally the conditions leading to pattern formation in pulsed fluidized
beds and the dimensionless numbers governing the phenomenon. We show that the onset
to the instability is universal for Geldart B (sandlike) particles and governed by the
hydrodynamical parameters = ua/(utφ¯) and f/fn, where ua and f are the amplitude
and frequency of the gas velocity, respectively, ut is the terminal velocity of the particles,
φ¯ is the average solids fraction, and fn is the natural frequency of the bed. These findings
suggest that patterns emerge as a result of a parametric resonance between the kinematic
waves originating from the oscillating gas flow and the bulk dynamics. Particle friction
plays virtually no role in the onset to pattern formation, but it is fundamental for pattern
selection and stabilization.