scholarly journals From arteries to boreholes: transient response of a poroelastic cylinder to fluid injection

Author(s):  
L. C. Auton ◽  
C. W. MacMinn

The radially outward flow of fluid through a porous medium occurs in many practical problems, from transport across vascular walls to the pressurization of boreholes in the subsurface. When the driving pressure is non-negligible relative to the stiffness of the solid structure, the poromechanical coupling between the fluid and the solid can control both the steady state and the transient mechanics of the system. Very large pressures or very soft materials lead to large deformations of the solid skeleton, which introduce kinematic and constitutive nonlinearity that can have a non-trivial impact on these mechanics. Here, we study the transient response of a poroelastic cylinder to sudden fluid injection. We consider the impacts of kinematic and constitutive nonlinearity, both separately and in combination, and we highlight the central role of driving method in the evolution of the response. We show that the various facets of nonlinearity may either accelerate or decelerate the transient response relative to linear poroelasticity, depending on the boundary conditions and the initial geometry, and that an imposed fluid pressure leads to a much faster response than an imposed fluid flux.

Author(s):  
L. C. Auton ◽  
C. W. MacMinn

The radially outward flow of fluid into a porous medium occurs in many practical problems, from transport across vascular walls to the pressurization of boreholes. As the driving pressure becomes non-negligible relative to the stiffness of the solid structure, the poromechanical coupling between the fluid and the solid has an increasingly strong impact on the flow. For very large pressures or very soft materials, as is the case for hydraulic fracturing and arterial flows, this coupling can lead to large deformations and, hence, to strong deviations from a classical, linear-poroelastic response. Here, we study this problem by analysing the steady-state response of a poroelastic cylinder to fluid injection. We consider the qualitative and quantitative impacts of kinematic and constitutive nonlinearity, highlighting the strong impact of deformation-dependent permeability. We show that the wall thickness (thick versus thin) and the outer boundary condition (free versus constrained) play a central role in controlling the mechanics.


2001 ◽  
Vol 21 (3) ◽  
pp. 222-230 ◽  
Author(s):  
Rolf K. Reed ◽  
Ansgar Berg ◽  
Eli-Anne B. Gjerde ◽  
Kristofer Rubin

2000 ◽  
Vol 279 (5) ◽  
pp. H2077-H2084 ◽  
Author(s):  
David B. Pearse ◽  
Patrice M. Becker

We previously found that increased intravascular pressure decreased ischemic lung injury by a nitric oxide (NO)-dependent mechanism (Becker PM, Buchanan W, and Sylvester JT. J Appl Physiol 84: 803–808, 1998). To determine the role of cyclic nucleotides in this response, we measured the reflection coefficient for albumin (ςalb), fluid flux ( J˙), cGMP, and cAMP in ferret lungs subjected to either 45 min (“short”; n = 7) or 180 min (“long”) of ventilated ischemia. Long ischemic lungs had “low” (1–2 mmHg, n = 8) or “high” (7–8 mmHg, n = 6) vascular pressure. Other long low lungs were treated with the NO donor ( Z)-1-[ N-(3-ammoniopropyl)- N-( n-propyl)amino]diazen-1-ium-1,2-diolate (PAPA-NONOate; 5 × 10−4 M, n = 6) or 8-bromo-cGMP (5 × 10−4 M, n = 6). Compared with short ischemia, long low ischemia decreased ςalb (0.23 ± 0.04 vs. 0.73 ± 0.08; P < 0.05) and increased J˙ (1.93 ± 0.26 vs. 0.58 ± 0.22 ml · min−1 · 100 g−1; P < 0.05). High pressure prevented these changes. Lung cGMP decreased by 66% in long compared with short ischemia. Lung cAMP did not change. PAPA-NONOate and 8-bromo-cGMP increased lung cGMP, but only 8-bromo-cGMP decreased permeability. These results suggest that ischemic vascular injury was, in part, mediated by a decrease in cGMP. Increased vascular pressure prevented injury by a cGMP-independent mechanism that could not be mimicked by administration of exogenous NO.


2018 ◽  
Vol 179 ◽  
pp. 221-226 ◽  
Author(s):  
Wang Jin ◽  
Kai-Yin Lo ◽  
Shih–En Chou ◽  
Scott W. McCue ◽  
Matthew J. Simpson

2021 ◽  
Vol 40 (6) ◽  
pp. 413-417
Author(s):  
Chunfang Meng ◽  
Michael Fehler

As fluids are injected into a reservoir, the pore fluid pressure changes in space and time. These changes induce a mechanical response to the reservoir fractures, which in turn induces changes in stress and deformation to the surrounding rock. The changes in stress and associated deformation comprise the geomechanical response of the reservoir to the injection. This response can result in slip along faults and potentially the loss of fluid containment within a reservoir as a result of cap-rock failure. It is important to recognize that the slip along faults does not occur only due to the changes in pore pressure at the fault location; it can also be a response to poroelastic changes in stress located away from the region where pore pressure itself changes. Our goal here is to briefly describe some of the concepts of geomechanics and the coupled flow-geomechanical response of the reservoir to fluid injection. We will illustrate some of the concepts with modeling examples that help build our intuition for understanding and predicting possible responses of reservoirs to injection. It is essential to understand and apply these concepts to properly use geomechanical modeling to design geophysical acquisition geometries and to properly interpret the geophysical data acquired during fluid injection.


1982 ◽  
Vol 242 (4) ◽  
pp. H557-H564
Author(s):  
B. C. Dillon ◽  
T. M. Saba

Reticuloendothelial (RE) clearance dysfunction, which can be induced by opsonic fibronectin deficiency, has been correlated with organ failure during sepsis. We investigate the role of opsonic fibronectin deficiency and RE blockade in modulating alterations in intestinal transvascular fluid balance induced by Pseudomonas bacteremia using an isolated, innervated, and autoperfused canine small intestinal segment. Intravenous infusion of gelatin-coated particles was used to induce fibronectin deficiency and RE blockade. Lymph flow and lymph/plasma (L/P) protein concentration ratios were stable following intravenous challenge with bacteria or gelatin-coated particles. In contrast, lymph flow increased and L/P ratio decreased significantly when bacteremia coexisted with particle-induced opsonic fibronectin deficiency and RE blockade. This elevation in lymph flow and decline in L/P ratio was associated with normal vascular permeability to albumin, IgG, and IgM. The increase in intestinal fluid flux during bacteremia with RE blockade appears to be due to an increase in microvascular hydrostatic pressure and not to an increase in vascular permeability. These findings emphasize a potentially important role for fibronectin and associated RE system function as determinants of fluid filtration during sepsis.


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