Combined effect of rheology and confining boundaries on spreading of gravity currents in porous media期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

按检索

Combined effect of rheology and confining boundaries on spreading of gravity currents in porous media

Institution:	1. Dipartimento di Ingegneria Civile, Ambiente Territorio e Architettura (DICATeA), Università di Parma, Parco Area delle Scienze, 181/A, 43124 Parma, Italy;2. Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali (DICAM), Università di Bologna, Viale Risorgimento, 2, 40136 Bologna, Italy;1. Division of Gastroenterology and Hepatology, University of Colorado Anschutz Medical Center, Aurora, Colorado;3. Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Illinois;4. Division of Gastroenterology and Hepatology, Yale University, New Haven, Connecticut;6. Division of Gastroenterology and Hepatology, Massachusetts General Hospital and Brigham and Women’s Hospital, Boston, Massachusetts;5. Division of Gastroenterology and Hepatology, Duke University, Durham, North Carolina;7. Division of Gastroenterology and Hepatology, Stanford University, Stanford, California;12. Division of Gastroenterology and Hepatology, Indiana University Hospital, Indianapolis, Indiana;8. Division of Gastroenterology and Hepatology, Washington University School of Medicine, St. Louis, Missouri;10. Division of Gastroenterology and Hepatology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California;9. Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine, Madison, Wisconsin;71. Division of Gastroenterology and Hepatology, Fox Chase Cancer Center, Philadelphia, Pennsylvania;123. Division of Gastroenterology and Hepatology, University of Florida, Gainesville, Florida;1. Consiglio Nazionale delle Ricerche, Istituto di Ricerca Sulle Acque, Via Salaria km 29.300, 00015 Monterotondo, RM, Italy;2. Dipartimento DICATAM, Università degli Studi di Brescia, Via Branze 43, 25123 Brescia, Italy;3. Consiglio Nazionale delle Ricerche, Istituto di Ricerca Sulle Acque, UOS Brugherio, Via del Mulino, 19, 20861 Brugherio, MB, Italy;1. Department of Obstetrics and Gynecology, Women''s Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China;2. Department of Obstetrics and Gynecology, Shenzhen University General Hospital, Guangdong, China;3. Department of Obstetrics and Gynecology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China;1. Petroleum Engineering Department, Petroleum University of Technology (PUT), Ahwaz, Iran;2. Petroleum Engineering Department, Amirkabir University of Technology, Tehran, Iran

Abstract:	One-dimensional flows of gravity currents within horizontal and inclined porous channels are investigated combining theoretical and experimental analysis to evaluate the joint effects of channel shape and fluid rheology. The parameter $β$ governs the shape of the channel cross section, while the fluid rheology is characterised by a power-law model with behaviour index n. Self-similar scalings for current length and height are obtained for horizontal and inclined channels when the current volume increases with time as $t^{α}$ .For horizontal channels, the interplay of model parameters $α, n$ , and $β$ governs the front speed, height, and aspect ratio of the current (ratio between the average height and the length). The dependency is modulated by two critical values of $α, α_{β} = n / (n + 1)$ and $α_{n} = (2 β + 1) / β$ . For all channel shapes, $α_{β}$ discriminates between currents whose height decreases ( $α < α_{β}$ ) or increases ( $α > α_{β}$ ) with time at a particular point. For all power-law fluids, $α_{n}$ discriminates between decelerated currents, with time-decreasing aspect ratio ( $α < α_{n}$ ), and accelerated currents, with time-increasing aspect ratio ( $α > α_{n}$ ). Only currents with time-decreasing height ( $α < α_{β}$ ) and aspect ratio ( $α < α_{n}$ ) respect model assumptions asymptotically; the former constraint is more restrictive than the latter.For inclined channels, a numerical solution in self-similar form is obtained under the hypothesis that the product of the channel inclination $θ$ and the slope of the free-surface is much smaller than unity; this produces a negligible error for $θ > 2 °$ , and is acceptable for $θ > 0.5 °$ . The action of gravity in inclined channels is modulated by both the behaviour index n and the shape factor $β$ . For constant flux, the current reaches at long times a steady state condition with a uniform thickness profile. In steep channels and for sufficiently long currents, the free-surface slope becomes entirely negligible with respect to channel inclination, and the constant thickness profile depends only on n.Theoretical results are validated by comparison with experiments (i) in horizontal and inclined channels with triangular or semicircular cross-section, (ii) with different shear-thinning fluids, and (iii) for constant volume and constant flux conditions. The experimental results show good agreement with theoretical predictions in the long-time regime.Our analysis demonstrates that self-similar solutions are able to capture the essential long-term behaviour of gravity currents in porous media, accounting for diverse effects such as non-Newtonian rheology, presence of boundaries, and channel inclination. This provides a relatively simple framework for sensitivity analysis, and a convenient benchmark for numerical studies.

Keywords:	Porous Gravity current Similarity solution Channel shape Non-Newtonian Laboratory experiments
本文献已被 ScienceDirect 等数据库收录！

设为首页 | 免责声明 | 关于勤云 | 加入收藏