Agradecimentos: Erick de Moraes Franklin is grateful to FAPESP (Grant no. 2012/19562-6) and to FAEPEX/UNICAMP (conv. 519.292, projects AP0008/2013 and 0201/14). Carlos Alvarez Zambrano is grateful to SENESCYT. The authors thank Rodolfo M. Tomazela for the help with the experimental device

Gravitational flow of grains in pipes is frequently encountered in industry. When the grains and pipes are size-constrained, granular flow may result in density waves consisting of alternate high- and low-compactness regions. This paper discusses the length scale of density waves that appear when...

Gravitational flow of grains in pipes is frequently encountered in industry. When the grains and pipes are size-constrained, granular flow may result in density waves consisting of alternate high- and low-compactness regions. This paper discusses the length scale of density waves that appear when fine grains fall vertically in pipes. A one-dimensional model and a linear stability analysis of the model are presented. The analysis suggests the presence of long-wavelength instability for the most unstable mode, moreover, a cutoff wavenumber from which the length scale is estimated. Finally, the model results are compared to experimental data

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2012/19562-6

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