Oscillation phenomena in gravity-driven drainage in coarse porous media

1992 ◽  
Vol 28 (7) ◽  
pp. 1849-1855 ◽  
Author(s):  
J. Pražák ◽  
M. Šír ◽  
F. Kubík ◽  
J. Tywoniak ◽  
C. Zarcone
Keyword(s):  
Porous Media ◽  
Gravity Driven ◽  
Coarse Porous Media

Monotonic Growth of Motile Microorganisms

2006 ◽  
Author(s):  
Alisa S. Vadasz ◽  
Peter Vadasz ◽  
Jeff G. Leid ◽  
Amanda Andrade ◽  
Emily Cope ◽  
...  
Keyword(s):  
Porous Media ◽  
Fluid Motion ◽  
Pure Fluids ◽  
Proposed Model ◽  
New Directions ◽  
Organism Growth ◽  
Gravity Driven ◽  
Microbial Proliferation ◽  
Micro Organisms ◽  
Convection In Porous Media

The research results presented here are part of a more extensive effort regarding sustained bioconvection in porous media. Bioconvection is the phenomenon of gravity driven fluid motion due to buoyancy forces resulting from density differences between the fluid and motile micro-organisms suspended in the fluid. While the field of bio-convection in pure fluids emerged substantially over the past decade the corresponding effects of bio-convection in porous media received much less attention, despite the fact that micro-organisms grow naturally in porous environments; soil, food and human tissues serve as basic examples. The research focuses in two major new directions. The first deals with the theoretical and experimental investigation of bio-convection in porous media. The second major new direction is linked to the sustainability of the bio-convection motion. The existing work on bio-convection in both pure fluids and porous media exclude micro-organism growth during the bio-convection because the time scales concerned were very short. However, when the question of the sustainability of this convection over long times arises, microorganism growth has to be accounted for. If sustained bio-convection in porous media is possible it opens the avenue to investigate its impact on microbial proliferation in soil, food and human tissue, an important avenue for application of the theoretical results. Then, if bio-convection enhances microbial proliferation it may be undesirable in some cases, e.g. in food, or it might be desirable if specific micro-organisms that can be used for contaminated soil remediation will be "helped" by the bio-convection process to access contaminated regions in the soil. The theoretical and experimental results presented in this paper reflect the process of monotonic growth of motile microorganisms (e.g. the PAOI strain of Pseudomonas Aeruginosa) to be included in the bioconvection process. A new proposed model is shown to be the appropriate one to better reflect both conceptually as well as practically the microbial growth process.

Phase-Field Models of Gravity-Driven Unsaturated Flow in Porous Media

2008 ◽  
Author(s):  
Luis Cueto-Felgueroso ◽  
Ruben Juanes
Keyword(s):  
Porous Media ◽  
Preferential Flow ◽  
Unsaturated Flow ◽  
Flow In Porous Media ◽  
Macroscopic Model ◽  
Wetting Front ◽  
Forming Mechanism ◽  
Gravity Driven ◽  
Pattern Forming ◽  
Models Of Gravity

Existing continuum models of multiphase flow in porous media are unable to explain why preferential flow (fingering) occurs during infiltration into homogeneous, dry soil. We identify a relevant pattern-forming mechanism in the dynamics of the wetting front, and present a macroscopic model that reproduces the experimentally observed features of fingered flows. The proposed model reveals a scaling between local and nonlocal interface phenomena in imbibition, and does not introduce new independent parameters. The predictions based on this model are consistent with experiments and theories of scaling in porous media.

scholarly journals An experimental study of flow and heat transfer in a differentially side heated cavity filled with coarse porous media

2019 ◽  
Vol 143 ◽  
pp. 118591 ◽  
Author(s):  
Iman Ataei-Dadavi ◽  
Nima Rounaghi ◽  
Manu Chakkingal ◽  
Sasa Kenjeres ◽  
Chris R. Kleijn ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Porous Media ◽  
Flow And Heat Transfer ◽  
Coarse Porous Media

Gravity driven instabilities in miscible non-Newtonian fluid displacements in porous media

2001 ◽  
Vol 290 (3-4) ◽  
pp. 286-304 ◽  
Author(s):  
V.M. Freytes ◽  
A. D’Onofrio ◽  
M. Rosen ◽  
C. Allain ◽  
J.P. Hulin
Keyword(s):  
Porous Media ◽  
Newtonian Fluid ◽  
Gravity Driven

A preliminary exploration of the micro-scale behaviour of capillary barrier effect using microfluidics

Géotechnique ◽  
2021 ◽  
pp. 1-25
Author(s):  
Liang-Tong Zhan ◽  
Guang-Yao Li ◽  
Bate Bate ◽  
Yun-Min Chen
Keyword(s):  
Porous Media ◽  
Water Flow ◽  
Water Movement ◽  
Barrier Effect ◽  
Capillary Barrier ◽  
Micro Scale ◽  
Flow Processes ◽  
Basic Physics ◽  
Throat Width ◽  
Coarse Porous Media

Capillary barrier effect (CBE) is employed in a large number of geotechnical applications to decrease deep percolation or increase slope stability. However, the micro-scale behaviour of CBE is rarely investigated, and thus hampers the scientific design of capillary barrier systems. This study uses microfluidics to explore the micro-scale behaviour of CBE. Capillarity-driven water flow processes from fine to coarse porous media with different pore topologies and sizes were performed and analysed. The experimental results demonstrate that the basic physics of CBE is the preferential water movement into the fine porous media due to the larger capillarity. The effects of CBE on water flow processes can be identified as delaying the occurrence of breakthrough into the coarse porous media and increasing the water storage of the fine porous media. The CBE can impede the increase of the normalized length and decrease the normalized width of the water front, suggesting that the two normalized parameters are potential indicators to assess the performance of CBE at micro scale. CBE can be formed in square and honeycomb networks with the ratio of coarse to fine pore throat width larger than 2.0 when gravity is neglected, and its performance can be affected by pore topology and size.

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