## 摘要

The dilute-to-dense transition of granular flow of particle size [Formula presented] is studied experimentally in a two-dimensional channel (width [Formula presented]) with confined exit (width [Formula presented]). Our results show that with fixed [Formula presented] and [Formula presented] there is a maximum inflow rate [Formula presented] above which the flow changes from dilute to dense and the outflow rate [Formula presented] drops abruptly from [Formula presented] to a dense rate [Formula presented]. A rescaled critical rate [Formula presented] is found to be a function of a scaling variable [Formula presented] only: [Formula presented], where [Formula presented]. This form of [Formula presented] suggests that the dilute-to-dense transition is a global property of the flow, unlike the jamming transition which depends only on [Formula presented]. Furthermore, the transition is found to occur when the area fraction of particles near the exit exceeds a critical value which is close to [Formula presented].

原文 | ???core.languages.en_GB??? |
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期刊 | Physical Review Letters |

卷 | 91 |

發行號 | 20 |

DOIs | |

出版狀態 | 已出版 - 2003 |