Intrapleural fluid movements described by a porous flow model

We injected technetium-labeled albumin (at a concentration similar to that of the pleural fluid) in the costal region of anesthetized dogs (n = 13) either breathing spontaneously or apneic. The decay rate of labeled activity at the injection site was studied with a gamma camera placed either in the anteroposterior (AP) or laterolateral (LL) projection. In breathing animals (respiratory frequency approximately 10 cycles/min), 10 min after the injection the activity decreased by approximately 50% on AP and approximately 20% on LL imaging; in apneic animals the corresponding decrease in activity was reduced to approximately 15 and approximately 3%, respectively. We considered label translocation from AP and LL imaging as a result of bulk flows of liquid along the costomediastinal and gravity-dependent direction, respectively. We related intrapleural flows to the hydraulic pressure gradients existing along these two directions and to the geometry of the pleural space. The pleural space was considered as a porous medium partially occupied by the mesh of microvilli protruding from mesothelial cells. Solution of the Kozeny-Carman equation for the observed flow velocities and pressure gradients yielded a mean hydraulic radius of the pathways followed by the liquid ranging from 2 to 4 microns. The hydraulic resistivity of the pleural space was estimated at approximately 8.5 x 10(5) dyn.s.cm-4, five orders of magnitude lower than that of interstitial tissue.

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Regional protein absorption rates from the pleural cavity in dogs

Journal of Applied Physiology ◽

10.1152/jappl.1985.58.6.2062 ◽

1985 ◽

Vol 58 (6) ◽

pp. 2062-2067 ◽

Cited By ~ 30

Author(s):

D. Negrini ◽

M. Pistolesi ◽

M. Miniati ◽

R. Bellina ◽

C. Giuntini ◽

...

Keyword(s):

Gamma Camera ◽

Time Course ◽

Saline Solution ◽

Pleural Cavity ◽

Pleural Space ◽

Regions Of Interest ◽

Functional Interaction ◽

Unit Surface ◽

Anesthetized Dogs ◽

Spontaneously Breathing

In five supine spontaneously breathing anesthetized dogs we injected into the pleural space 0.5–1 ml of saline solution containing 2 mg/ml albumin labeled with technetium-99m. By use of a gamma camera placed horizontally over the chest, we followed, up to 120 min, the activity over the whole lung and over the preferential accumulation areas of the label (regions of interest, ROI) that corresponded to the apical, mediastinal, and laterodiaphragmatic regions. Activities were corrected for the decay rate of the isotope used. On the average, the activity over the whole lung decreased by 27% up to 120 min. The overall activity over the ROI amounted to 44.3% after the injection and decreased to 24% of total at 120 min, thus accounting for 75% of the total decrease in activity. At 10 min, the activity per unit surface of the gamma camera image (As) was from 2.2- to 5.7-fold higher over the ROI than for the rest of the lung image. The decrease of As at 120 min was 18-, 13-, and 5-fold greater for mediastinal, diaphragmatic, and apical regions, respectively, compared with the rest of the lung image. The time course of the changes in As are discussed in terms of regional albumin egress rate based on the functional interaction between the Starling and the lymphatic mechanisms.

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Porous parachute modelling with an Euler-Lagrange coupling

European Journal of Computational Mechanics ◽

10.13052/remn.16.385-399 ◽

2007 ◽

pp. 385-399

Author(s):

Nicolas Aquelet ◽

Jason Wang

Keyword(s):

Porous Medium ◽

Flow Model ◽

Test Case ◽

Element Formulation ◽

Porous Flow ◽

Air Stream ◽

Thin Porous Media ◽

Coupling Force ◽

Lagrangian Finite Element ◽

Updated Lagrangian

A newly developed approach for tridimensional fluid-structure interaction with a deformable thin porous media is presented. The method presented couples a Arbitrary Lagrange Euler formulation for the fluid dynamics and a updated Lagrangian finite element formulation for the thin porous medium dynamics. The interaction between the fluid and porous medium are handled by a Euler-Lagrange coupling, for which the fluid and structure meshes are superimposed without matching. The coupling force is computed with an Ergun porous flow model. As test case, the method is applied to an anchored air parachute placed in an air stream.

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Pleural liquid pressure gradients and intrapleural distribution of injected bolus

Journal of Applied Physiology ◽

10.1152/jappl.1984.56.2.526 ◽

1984 ◽

Vol 56 (2) ◽

pp. 526-532 ◽

Cited By ~ 30

Author(s):

G. Miserocchi ◽

M. Pistolesi ◽

M. Miniati ◽

C. R. Bellina ◽

D. Negrini ◽

...

Keyword(s):

Gamma Camera ◽

Pressure Gradients ◽

Liquid Pressure ◽

Anesthetized Dogs ◽

Frontal Projection ◽

Pleural Liquid Pressure

In supine anesthetized dogs we measured pleural liquid pressure (Pliq) in mediastinal, diaphragmatic, apical, and costal regions at different lung heights during eupneic breathing. At end expiration and at a given height, Pliq was similar in the costal and apical regions, but it was lower in the diaphragmatic and mediastinal compartments. Inspiratory swings toward lower values were progressively greater with increasing height and moving from costal to apical, diaphragmatic and mediastinal compartments. Thus during inspiration, at any height, the costomediastinal and costodiaphragmatic Pliq difference increased while a costoapical difference developed. One minute after injection of 0.5–1 ml of saline at different points within the cavity, end-expiratory liquid pressure became higher on the average by 0.45, 1.55, and 0.55 cmH2O in the apical, mediastinal, and diaphragmatic compartments, respectively, while no change was observed on costal side. These results suggested liquid accumulation in the compartments displaying a lower Pliq. This was confirmed by following, with a gamma camera, on a frontal projection of the lung, the intrapleural distribution of a bolus containing 99mTc-labeled albumin injected at various places.

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Euler-Lagrange Coupling With Deformable Porous Shells

Volume 4: Fluid Structure Interaction, Parts A and B ◽

10.1115/pvp2006-icpvt-11-93430 ◽

2006 ◽

Cited By ~ 1

Author(s):

N. Aquelet ◽

J. Wang ◽

B. A. Tutt ◽

I. Do ◽

H. Chen

Keyword(s):

Porous Medium ◽

Flow Model ◽

Test Case ◽

Element Formulation ◽

Porous Flow ◽

Air Stream ◽

Thin Porous Media ◽

Coupling Force ◽

Lagrangian Finite Element ◽

Updated Lagrangian

A newly developed approach for tridimensional fluid-structure interaction with a deformable thin porous media is presented under the framework of the LS-DYNA software. The method presented couples a Arbitrary Lagrange Euler formulation for the fluid dynamics and a updated Lagrangian finite element formulation for the thin porous medium dynamics. The interaction between the fluid and porous medium are handled by a Euler-Lagrange coupling, for which the fluid and structure meshes are superimposed without matching. The coupling force is computed with an anisotropic Ergun porous flow model. As test case, the method is applied to an anchored porous MIL-c-7020 type III fabric placed in an air stream.

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Forced Convection in a Channel Filled With Porous Medium, Including the Effects of Flow Inertia, Variable Porosity, and Brinkman Friction

Journal of Heat Transfer ◽

10.1115/1.3248198 ◽

1987 ◽

Vol 109 (4) ◽

pp. 880-888 ◽

Cited By ~ 121

Author(s):

D. Poulikakos ◽

K. Renken

Keyword(s):

Porous Medium ◽

Forced Convection ◽

Flow Model ◽

Saturated Porous Medium ◽

Porous Matrix ◽

Parallel Plates ◽

Entry Length ◽

Variable Porosity ◽

Flow Inertia ◽

Temperature And Flow Fields

This paper presents a series of numerical simulations which aim to document the problem of forced convection in a channel filled with a fluid-saturated porous medium. In modeling the flow in the channel, the effects of flow inertia, variable porosity and Brinkman friction are taken into account. Two channel configurations are investigated: parallel plates and circular pipe. In both cases, the channel wall is maintained at constant temperature. It is found that the general flow model predicts an overall enhancement in heat transfer between the fluid/porous matrix composite and the walls, compared to the predictions of the widely used Darcy flow model. This enhancement is reflected in the increase of the value of the Nusselt number. Important results documenting the dependence of the temperature and flow fields in the channel as well as the dependence of the thermal entry length on the problem parameters are also reported in the course of the study.

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INTERACTION OF PULSATILE FLOW ON THE PERISTALTIC MOTION OF A MAGNETO-MICROPOLAR FLUID THROUGH POROUS MEDIUM IN A FLEXIBLE CHANNEL: BLOOD FLOW MODEL

International Journal of Pure and Apllied Mathematics ◽

10.12732/ijpam.v94i3.3 ◽

2014 ◽

Vol 94 (3) ◽

Cited By ~ 1

Author(s):

Kh.S. Mekheimer ◽

M.S. Mohamed

Keyword(s):

Porous Medium ◽

Blood Flow ◽

Pulsatile Flow ◽

Micropolar Fluid ◽

Flow Model ◽

Peristaltic Motion ◽

Blood Flow Model

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A Semi-Analytical Model for Predicting Horizontal Well Performances in Fractured Gas Reservoirs With Bottom-Water and Different Fracture Intensities

Journal of Energy Resources Technology ◽

10.1115/1.4040201 ◽

2018 ◽

Vol 140 (10) ◽

Cited By ~ 15

Author(s):

Yongsheng Tan ◽

Haitao Li ◽

Xiang Zhou ◽

Beibei Jiang ◽

Yongqing Wang ◽

...

Keyword(s):

Porous Medium ◽

Horizontal Well ◽

Bottom Water ◽

Flow Model ◽

Numerical Solutions ◽

Gas Reservoirs ◽

Gas Reservoir ◽

New Model ◽

Well Completion ◽

Wellbore Pressure

Numerical simulation and prediction studies on horizontal well performances in gas reservoir are foundation for optimizing horizontal well completion process. To gain more understanding on this theory, a steady-state reservoir model coupling with wellbore is developed in the fractured gas reservoirs with bottom-water and different fracture intensities to predict the horizontal well performances. Based on the equivalent flow assumption, the fractured porous medium is transformed into anisotropic porous medium so that the gas reservoir flow model can be developed as a new model that incorporates formation permeability heterogeneity, reservoir anisotropy, and gas reservoir damage. The wellbore flow model which considers pressure drops in the tubing is applied. We compare this paper model solutions for inflow profile along the well to the numerical solutions obtained from a commercial simulator (ECLIPSE 2011), and the result shows a very good agreement. Moreover, sensitive analysis, in terms of various linear densities of fractures, matrix permeability, fracture width, and wellbore pressure drop, is implemented. The results show that the new model developed in this study can obtain a more practical representation to simulate the horizontal wells performance in fractured gas reservoir with different fracture intensities and bottom-water, thus can be used to optimize the parameters in horizontal well completion of fractured gas reservoirs with different fracture intensities and bottom-water.

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