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サイトウ クニヤス
Kuniyasu Saitoh
齊藤 国靖 所属 京都産業大学 理学部 物理科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2015/04 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | The role of gravity or pressure and contact stiffness in granular rheology |
| 執筆形態 | その他 |
| 掲載誌名 | New Journal of Physics |
| 出版社・発行元 | IOP PUBLISHING LTD |
| 巻・号・頁 | 17 |
| 著者・共著者 | Singh, A.,Magnanimo, V.,Saitoh, K.,Luding, S. |
| 概要 | The steady-state shear rheology of granular materials is investigated in slow quasistatic and inertial flows. The effect of gravity (thus the local pressure) and the often-neglected contact stiffness are the focus of this study. A series of particle simulations are performed on a weakly frictional granular assembly in a split-bottom geometry considering various magnitudes of gravity and contact stiffnesses. While traditionally the inertial number, i.e., the ratio of stress to strain-rate time scales, is used to describe the flow rheology, we report that a second dimensionless number, the ratio of softness and stress time scales, must also be included to characterize the bulk flow behavior. For slow, quasistatic flows, the density increases while the effective (macroscopic) friction decreases with increase in either particle softness or local pressure. This trend is added to the mu(I) rheology and can be traced back to the anisotropy in the contact network, displaying a linear correlation between the effective friction coefficient and deviatoric fabric in the steady state. When the external rotation rate is increased towards the inertial regime, for a given gravity field and contact stiffness, the effective friction increases faster than linearly with the deviatoric fabric. |
| DOI | 10.1088/1367-2630/17/4/043028 |
| ISSN | 1367-2630 |
| PermalinkURL | http://www.scopus.com/inward/record.url?eid=2-s2.0-84930625715&partnerID=MN8TOARS |
| researchmap用URL | http://orcid.org/0000-0002-3511-2710 |