Splitting of a two-dimensional liquid plug at an airway bifurcation

Vaughan, Benjamin L.; Grotberg, James B.

doi:10.1017/jfm.2016.106

Cited by 10 publications

(9 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Filoche et al 40,41 used the one-dimensional mathematical model to develop a three-dimensional lung airway model of SRT and compared it to experiments with rats' lungs. 42 Vaughan and Grotberg 43 used the finite element method and investigated the split process of a liquid plug by a two-dimensional bifurcation model under the influence of a transverse gravitational field and showed qualitative agreement with Zheng et al 37 During liquid plug splitting at bifurcation, the air-liquid interface contracts/stretches, and breaks/merges. There are some computational methods that can handle large deformations and topological changes in interfaces.…”

Section: Splitting Of a Three-dimensional Liquid Plug At An Airway Bi...mentioning

confidence: 60%

Splitting of a three-dimensional liquid plug at an airway bifurcation

et al. 2022

Self Cite

View full text Add to dashboard Cite

Employing the moving particles semi-implicit (MPS) method, this study presents a numerical framework for solving the Navier-Stokes equations for the propagation and the split of a liquid plug through a three-dimensional air-filled bifurcating tube, where the inner surface is coated by a thin fluid film, and surface tension acts on the air-liquid interface. The detailed derivation of a modified MPS method to handle the air-liquid interface of liquid plugs is presented. When the front air-liquid interface of the plug splits at the bifurcation, the interface deforms quickly and causes large wall shear stress. We observe that the presence of a transverse gravitational force causes asymmetries in plug splitting, which becomes more pronounced as the capillary number decreases or the Bond number increases. We also observe that there exists a critical capillary number below which the plug does not split into two daughter tubes, but propagates into the lower daughter tube only. In order to deliver the plug into the upper daughter tube, the driving pressure to push the plug is required to overcome the hydrostatic pressure due to gravity. These tendencies agree with our previous experimental and theoretical studies.

show abstract

Section: Splitting Of a Three-dimensional Liquid Plug At An Airway Bi...mentioning

confidence: 60%

Splitting of a three-dimensional liquid plug at an airway bifurcation

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…Non-axisymmetric perturbations to the exterior of a liquid-lined cylinder can also influence film distributions [28]. Our study complements the extensive literature on liquid plugs in lung airways, which focuses primarily on plug displacement under forcing, with studies focusing on the role of inertia [9], wall flexibility [22,50], surfactant [10,45], dynamical effects including plug rupture [12,23,32,42], gravity [40,51], interactions with bifurcations [43,52] and yielding behaviour [24,49].…”

Section: Introductionmentioning

confidence: 74%

Trapping and displacement of liquid collars and plugs in rough-walled tubes

Feng

Jensen

2017

Phys. Rev. Fluids

View full text Add to dashboard Cite

A liquid film wetting the interior of a long circular cylinder redistributes under the action of surface tension to form annular collars or occlusive plugs. These equilibrium structures are invariant under axial translation within a perfectly smooth uniform tube and therefore can be displaced axially by very weak external forcing. We consider how this degeneracy is disrupted when the tube wall is rough, and determine threshold conditions under which collars or plugs resist displacement under forcing. Wall roughness is modelled as a non-axisymmetric Gaussian random field of prescribed correlation length and small variance, mimicking some of the geometric irregularities inherent in applications such as lung airways. The thin film coating this surface is modelled using lubrication theory. When the roughness is weak, we show how the locations of equilibrium collars and plugs can be identified in terms of the azimuthally-averaged tube radius; we derive conditions specifying equilibrium collar locations under an externally imposed shear flow, and plug locations under an imposed pressure gradient. We use these results to determine the probability of external forcing being sufficient to displace a collar or plug from a rough-walled tube, when the tube roughness is defined only in statistical terms.

show abstract

“…For example, rather than 70 dyn/cm we use 30 dyn/cm. In addition, we have explored 2D plug splitting and its effects on the split ratio [61]. The fate of surfactant once it coats the airways or has entered the acinus is also a challenging field of study.…”

Section: Discussionmentioning

confidence: 99%

Surfactant delivery in rat lungs: Comparing 3D geometrical simulation model with experimental instillation

Kazemi¹,

Louis²,

Isabey³

et al. 2019

PLoS Comput Biol

Self Cite

View full text Add to dashboard Cite

Surfactant Replacement Therapy (SRT), which involves instillation of a liquid-surfactant mixture directly into the lung airway tree, is a major therapeutic treatment in neonatal patients with respiratory distress syndrome (RDS). This procedure has proved to be remarkably effective in premature newborns, inducing a five-fold decrease of mortality in the past 35 years. Disappointingly, its use in adults for treating acute respiratory distress syndrome (ARDS) experienced initial success followed by failures. Our recently developed numerical model has demonstrated that transition from success to failure of SRT in adults could, in fact, have a fluid mechanical origin that is potentially reversible. Here, we present the first numerical simulations of surfactant delivery into a realistic asymmetric conducting airway tree of the rat lung and compare them with experimental results. The roles of dose volume (VD), flow rate, and multiple aliquot delivery are investigated. We find that our simulations of surfactant delivery in rat lungs are in good agreement with our experimental data. In particular, we show that the monopodial architecture of the rat airway tree plays a major role in surfactant delivery, contributing to the poor homogeneity of the end distribution of surfactant. In addition, we observe that increasing VD increases the amount of surfactant delivered to the acini after losing a portion to coating the involved airways, the coating cost volume, VCC. Finally, we quantitatively assess the improvement resulting from a multiple aliquot delivery, a method sometimes employed clinically, and find that a much larger fraction of surfactant reaches the alveolar regions in this case. This is the first direct qualitative and quantitative comparison of our numerical model with experimental studies, which enhances our previous predictions in adults and neonates while providing a tool for predicting, engineering, and optimizing patient-specific surfactant delivery in complex situations.

show abstract

Splitting of a two-dimensional liquid plug at an airway bifurcation

Cited by 10 publications

References 54 publications

Splitting of a three-dimensional liquid plug at an airway bifurcation

Splitting of a three-dimensional liquid plug at an airway bifurcation

Trapping and displacement of liquid collars and plugs in rough-walled tubes

Surfactant delivery in rat lungs: Comparing 3D geometrical simulation model with experimental instillation

Contact Info

Product

Resources

About