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
Author(s):  
Alisa S. Vadasz ◽  
Peter Vadasz ◽  
Jeff G. Leid ◽  
Amanda Andrade ◽  
Emily Cope ◽  
...  

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.


Author(s):  
Luis Cueto-Felgueroso ◽  
Ruben Juanes

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.


2020 ◽  
Vol 235 ◽  
pp. 103708
Author(s):  
Scott C. Hauswirth ◽  
Christopher A. Bowers ◽  
Christopher P. Fowler ◽  
Pamela B. Schultz ◽  
Amanda Dye Hauswirth ◽  
...  

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