Computational predictions for viscoelastic filament stretching flows: ALE methods and free-surface techniques (CM and VOF)

Sujatha, K.; Matallah, H.; Banaai, M.J.; Webster, M.F.

doi:10.1016/j.jnnfm.2006.03.009

Cited by 20 publications

(22 citation statements)

References 35 publications

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“…Interactions of the phases become more significant since the dimensions shrinks due to the pressure difference caused by surface-tension. In principle, the choice of multiphase method is mainly based on the type of the problem and degree of precision for which the resulting interphase is to be determined (Sujatha et al, 2006). The major limitation of Lagrangian methods is that they cannot track the interface.…”

Section: The Governing Equationsmentioning

confidence: 99%

Direct numerical simulation of water droplet coalescence in the oil

Mohammadi

Shahhosseini

Bayat³

2012

International Journal of Heat and Fluid Flow

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Section: The Governing Equationsmentioning

confidence: 99%

Direct numerical simulation of water droplet coalescence in the oil

Mohammadi

Shahhosseini

Bayat³

2012

International Journal of Heat and Fluid Flow

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“…This mesh choice was adopted after conducting an intensive mesh refinement study, the details of which are reported in [30]. The mesh must adjust in time, being stretched and distorted, its movement being controlled by the time-step and remeshing algorithm, see [9,31].…”

Section: Problem Specificationmentioning

confidence: 99%

Modelling filament stretching flows with strain-hardening models and sub-cell approximations

Matallah

Banaai

Sujatha

et al. 2006

Journal of Non-Newtonian Fluid Mechanics

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This article analyses the transient viscoelastic response of strain-hardening fluids in filament stretching flows. We utilise an Arbitrary Lagrangian/Eulerian temporal approach (ALE), coupled with a particle-tracking procedure for free-surface movement and a hybrid finite volume/element method upon the domain. We are able to contrast findings between Oldroyd, Giesekus and linear Phan-Thien/Tanner models, and distinguish between single and multi-mode implementations. In this manner, we identify the impact that greater severe strainhardening has in this transient flow context. Contributions from shear-thinning rheology may be gathered in particular by comparing single-mode solution response between a shearthinning Giesekus and a constant shear viscosity Oldroyd-B model. A parameter study on inertial and surface tension effects has been undertaken, where we isolate the occurrence of asymmetries in the flow under certain conditions, leading to the onset and formulation of bead-like structures. This elucidates the specific localised influence that surface tension and gravitational forces have upon some stretching filament flows.

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“…Automatic adaptive remeshing techniques were later developed in [21,22] to give more flexibility to transient Lagrangian simulations of nonNewtonian free-surface flows when large deformations occur. The arbitrary-Lagrangian-Eulerian method has also been used to simulate the filament stretching [23,24] and extrudate swell [25,26] of viscoelastic liquids. Finally, a few works on the simulation of free-surface viscoelastic flows with the mesh-free smoothed particle hydrodynamics method have been reported in [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of the planar extrudate swell of pseudoplastic and viscoelastic fluids with the streamfunction and the VOF methods

Comminal

Pimenta

Hattel

et al. 2018

Journal of Non-Newtonian Fluid Mechanics

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. Numerical simulation of the planar extrudate swell of pseudoplastic and viscoelastic fluids with the streamfunction and the VOF methods. Journal of Non-Newtonian Fluid Mechanics, 252, 1-18. DOI: 10.1016/j.jnnfm.2017 A B S T R A C TWe present an Eulerian free-surface flow solver for incompressible pseudoplastic and viscoelastic non-Newtonian fluids. The free-surface flow solver is based on the streamfunction flow formulation and the volume-of-fluid method. The streamfunction solver computes the vector potential of a solenoidal velocity field, which ensures by construction the mass conservation of the solution, and removes the pressure unknown. Pseudoplastic liquids are modelled with a Carreau model. The viscoelastic fluids are governed by differential constitutive models reformulated with the log-conformation approach, in order to preserve the positive-definiteness of the conformation tensor, and to circumvent the high Weissenberg number problem. The volume fraction of the fluid is advected with a geometric conservative unsplit scheme that preserves a sharp interface representation. For the sake of comparison, we also implemented an algebraic advection scheme for the liquid volume fraction. The proposed numerical method is tested by simulating the planar extrudate swell with the Carreau, Oldroyd-B and Giesekus constitutive models. The swell ratio of the extrudates are compared with the data available in the literature, as well as with numerical simulations performed with the open-source rheoTool toolbox in OpenFOAM ® . While the simulations of the generalized Newtonian fluids achieved mesh independence for all the methods tested, the flow simulations of the viscoelastic fluids are more sensitive to mesh refinement and the choice of numerical scheme. Moreover, the simulations of Oldroyd-B fluid flows above a critical Weissenberg number are prone to artificial surface instabilities. These numerical artifacts are due to discretization errors within the Eulerian surface-capturing method. However, the numerical issues arise from the stress singularity at the die exit corner, and the unphysical predictions of the Oldroyd-B model in the skin layer of the extrudate after the die exit, where large extensional deformations occur.

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Computational predictions for viscoelastic filament stretching flows: ALE methods and free-surface techniques (CM and VOF)

Cited by 20 publications

References 35 publications

Direct numerical simulation of water droplet coalescence in the oil

Direct numerical simulation of water droplet coalescence in the oil

Modelling filament stretching flows with strain-hardening models and sub-cell approximations

Numerical simulation of the planar extrudate swell of pseudoplastic and viscoelastic fluids with the streamfunction and the VOF methods

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