Steady flow of a viscoelastic film over an inclined plane featuring periodic slits

Pettas, D.; Dimakopoulos, Yannis; Tsamopoulos, John

doi:10.1016/j.jnnfm.2020.104243

Cited by 8 publications

(7 citation statements)

References 54 publications

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“…Finally, combining their results with previous in vivo measurements, they additionally found that the viscoelasticity of human blood plasma must not be ignored when examining the flow of whole blood in micro-tube, such as arterioles or capillaries. Consequently, we adopt viscoelastic constitutive modelling via the Phan-Thien-Tanner (or PTT) model [ 67 , 68 , 69 ]. The model is an extension of the Maxwell model accompanied with the upper convected derivative to include a function dependent upon

, the trace of the viscoelastic stress tensor due to plasma proteins.…”

Section: Problem Formulationmentioning

confidence: 99%

Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Steady-State Blood Flow in Microtubes

2021

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The present work focuses on the in-silico investigation of the steady-state blood flow in straight microtubes, incorporating advanced constitutive modeling for human blood and blood plasma. The blood constitutive model accounts for the interplay between thixotropy and elasto-visco-plasticity via a scalar variable that describes the level of the local blood structure at any instance. The constitutive model is enhanced by the non-Newtonian modeling of the plasma phase, which features bulk viscoelasticity. Incorporating microcirculation phenomena such as the cell-free layer (CFL) formation or the Fåhraeus and the Fåhraeus-Lindqvist effects is an indispensable part of the blood flow investigation. The coupling between them and the momentum balance is achieved through correlations based on experimental observations. Notably, we propose a new simplified form for the dependence of the apparent viscosity on the hematocrit that predicts the CFL thickness correctly. Our investigation focuses on the impact of the microtube diameter and the pressure-gradient on velocity profiles, normal and shear viscoelastic stresses, and thixotropic properties. We demonstrate the microstructural configuration of blood in steady-state conditions, revealing that blood is highly aggregated in narrow tubes, promoting a flat velocity profile. Additionally, the proper accounting of the CFL thickness shows that for narrow microtubes, the reduction of discharged hematocrit is significant, which in some cases is up to 70%. At high pressure-gradients, the plasmatic proteins in both regions are extended in the flow direction, developing large axial normal stresses, which are more significant in the core region. We also provide normal stress predictions at both the blood/plasma interface (INS) and the tube wall (WNS), which are difficult to measure experimentally. Both decrease with the tube radius; however, they exhibit significant differences in magnitude and type of variation. INS varies linearly from 4.5 to 2 Pa, while WNS exhibits an exponential decrease taking values from 50 mPa to zero.

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, the trace of the viscoelastic stress tensor due to plasma proteins.…”

Section: Problem Formulationmentioning

confidence: 99%

Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Steady-State Blood Flow in Microtubes

2021

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“…The viscous length varies over a much broader range than the capillary length due to the broader variation of μ * , while surface tension and density of most common polymeric solutions vary over a much shorter range. Hereafter, we scale all lengths by l * c ; the same choice was also made by (Trifonov 2014;Pettas et al 2019a;Pettas, Dimakopoulos & Tsamopoulos 2020). By scaling all lengths by the capillary length, l * c , the dimensionless lengths of the substrate geometry become independent of the primitive flow rate.…”

Section: Problem Formulationmentioning

confidence: 99%

“…Hereafter, we scale all lengths by ; the same choice was also made by (Trifonov 2014; Pettas et al . 2019 a ; Pettas, Dimakopoulos & Tsamopoulos 2020). By scaling all lengths by the capillary length, , the dimensionless lengths of the substrate geometry become independent of the primitive flow rate.…”

Section: Problem Formulationmentioning

confidence: 99%

“…Later on, Pavlidis, Dimakopoulos & Tsamopoulos (2010) and Pavlidis et al (2016) solved the 2-D momentum equations for a viscoelastic film flowing over a topography featuring rectangular trenches employing the exponential Phan-Thien Tanner (ePTT) model (Phan-Thien 1978), which introduces the most common viscoelastic properties. Recently, Pettas, Dimakopoulos & Tsamopoulos (2020) investigated the steady flow of a polymer solution over a partially coated substrate.…”

Section: Introductionmentioning

confidence: 99%

“…In all the aforementioned studies, the film was considered to wet the solid structure completely. We should mention, however, that a complete wetting state cannot always be achieved, especially when the substrate is deep and aligned with the gravitational force; hence, air may be entrapped inside the topographical features (Giacomello et al 2012;Karapetsas et al 2017;Pettas et al 2017;Pettas, Dimakopoulos & Tsamopoulos 2020).…”

Section: Introductionmentioning

confidence: 99%

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Stability analysis of viscoelastic film flows over an inclined substrate with rectangular trenches

et al. 2021

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Shear stress and intravascular pressure effects on vascular dynamics: two-phase blood flow in elastic microvessels accounting for the passive stresses

Giannokostas

Dimakopoulos

Tsamopoulos

2022

Biomech Model Mechanobiol

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Steady flow of a viscoelastic film over an inclined plane featuring periodic slits

Cited by 8 publications

References 54 publications

Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Steady-State Blood Flow in Microtubes

Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Steady-State Blood Flow in Microtubes

Stability analysis of viscoelastic film flows over an inclined substrate with rectangular trenches

Shear stress and intravascular pressure effects on vascular dynamics: two-phase blood flow in elastic microvessels accounting for the passive stresses

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