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Natural convection within a non-uniformly heated cavity partly filled with a shear-thinning nanofluid and partly with air J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2021-01-23 Asma Ouahouah; Nabila Labsi; Xavier Chesneau; Youb Khaled Benkahla
Natural convection in a cavity with non-uniformly heated bottom wall, partly filled with a non-Newtonian nanofluid (Cu-water) layer and partly with air layer is studied numerically in this work. The mixture of water and copper nanoparticles shows a shear-thinning rheological behavior. The nanofluid's rheological parameters, i.e. consistency and flow index, are obtained according to the solid volume
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Microconfined electroosmotic flow of a complex fluid with asymmetric charges: Interplay of fluid rheology and physicochemical heterogeneity J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2021-01-15 Bimalendu Mahapatra; Aditya Bandopadhyay
We report a study on the micro-confined electroosmotic flow of an Oldroyd-B fluid over a surface having asymmetric charge modulation. We have employed a combination of regular and matched asymptotic expansion to obtain the analytical solution. We have also carried out a full numerical simulation of the physicochemical problem in order to assess the full parameter space of the problem. The analytical
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Sudden strain changes in non-colloidal suspensions J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2021-01-20 Arif Mahmud; Shaocong Dai; Roger I. Tanner
The response of non-colloidal suspensions to sudden strains and sudden changes of strain rate is explored. The matrix fluids were silicone oil and glycerol/water. A Oldroyd-B model of the suspensions augmented by a friction element gives a description of the shear stresses which agrees with experiment. Friction becomes dominant for volume fractions greater than 0.3.
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Comment on the paper “Wall effects for spherical particle in confined shear-thickening fluids, Shuai Tian, Journal of Non-Newtonian Fluid Mechanics 257(2018) 13-21” J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2021-01-18 Asterios Pantokratoras
The present comment concerns a wrong comparison made in the above paper.
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Electro-thermo-convection in non-Newtonian power-law fluids within rectangular enclosures J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-31 Zheng-Gang Su; Tian-Fu Li; Kang Luo; Jian Wu; Hong-Liang Yi
Electro-thermo-convection is a typical interdisciplinary problem, that has been widely studied in terms of its physical phenomena in Newtonian fluids. As an essential supplement to the study of electrohydrodynamics, electro-thermo-convection in power-law fluids within rectangular enclosures is investigated in this paper. Two geometrical configurations are considered, namely differentially heated vertical
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Sedimentation behavior of a spherical particle in a Giesekus fluid: A CFD-DEM solution J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-30 Ali Heydari-Beni; Roman J. Shor; Giovanniantonio Natale
The sedimentation of a spherical solid particle in viscoelastic fluids was studied using a Giesekus model by development of a direct numerical simulation solver based on fully-resolved and immersed boundary methods to understand the complex non-Newtonian fluid flow and spherical particle dynamics. Two benchmark problems were modeled to evaluate the accuracy of the developed solver and excellent agreement
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Temporal instability of a viscoelastic liquid thread surrounded by another viscoelastic fluid in presence of insoluble surfactant and inertia J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-28 Dongdong He; Jonathan J. Wylie
In recent years, there has been controversy in the literature regarding the role of viscoelasticity in determining the onset of stability for a viscoelastic thread surrounded by another viscoelastic fluid. Whereas a number of authors have found that viscoelasticity serves to destabilize the system, Patrascu and Balan (2018) obtained very different results. They considered a very simple canonical system
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The structure factor in flowing wormlike micellar solutions J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-19 C. Fierro; L. Medina; F. Bautista; E.E. Herrera-Valencia; F. Calderas; O. Manero
In this work we present theoretical and experimental studies on the structure factor in micellar systems. Cetyl trimethyl ammonium tosilate (CTAT) solutions in absence of salts exhibit a flow behavior similar to polymer solutions, while upon an increase in the ionic strength with NaCl, their behavior changes to that of a kinetic-controlled breakage-reformation process. The relaxation mechanism thus
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Temporal analysis of a non-Newtonian liquid jet in a compressible gas J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-11 Xin-Tao Wang; Zhi Ning; Ming Lü
The temporal instability behavior of a non-Newtonian liquid jet in a compressible gas is investigated theoretically. A corotational Jeffreys model is used for describing the viscoelastic liquid state. The dispersion relation is solved by Chebyshev collocation method. Besides, the effects of compressibility of gas, Reynolds number, elasticity number, and the ratio of deformation retardation time to
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Electrohydrodynamic instability of confined viscoelastic liquid jets J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-03 Rishav Agrawal; V. Shankar
Linear stability analysis is performed to study the electrohydrodynamic instability of viscoelastic jets subjected to axisymmetric (m=0) and first non-axisymmetric (m=1) perturbations in the creeping-flow limit. The viscoelastic liquid jet is under the influence of a radially applied electric field induced by a concentrically placed electrode located at a finite gap width from the jet. The leaky dielectric
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Linear stability analysis of the Poiseuille flow of a stratified non-Newtonian suspension: Application to microcirculation J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-05 Lorenzo Fusi; Angiolo Farina; Giuseppe Saccomandi
We investigate the linear stability of a unidirectional flow of a suspension (blood) modeling the latter as a inhomogeneous non-Newtonian fluid in which viscosity depends on both the red blood cell concentration (RBCs) and the shear rate. We consider small vessels like arteries terminal branches, arterioles or venules, where the RBCs do not distribute uniformly on the cross section. The stability analysis
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Numerical simulation of non-isothermal viscoelastic flows at high Weissenberg numbers using a finite volume method on general unstructured meshes J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-11-30 Stefanie Meburger; Matthias Niethammer; Dieter Bothe; Michael Schäfer
In this numerical study, an original approach to simulate non-isothermal viscoelastic fluid flows at high Weissenberg numbers is presented. Stable computations over a wide range of Weissenberg numbers are assured by using the root conformation approach in a finite volume framework on general unstructured meshes. The numerical stabilization framework is extended to consider thermo-rheological properties
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A quantitative evaluation of viscosity regularization in predicting transient flows of viscoplastic fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-17 A. Ahmadi; I. Karimfazli
We present an assessment of viscosity regularization (VR) in predicting transient flows of viscoplastic fluids (VPF). Although VR has been the most popular approach for computational studies of VPF in the last decade, the understanding of its effects on the predicted flow behaviour has remained largely qualitative. To reveal the effects of VR, we present a systematic quantitative comparison of the
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On forcespinning of nonlinear rotating jets of viscoelastic Boger fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-12-04 D.N. Riahi
We consider forcespinning (FS) of nonlinear three-dimensional rotating viscoelastic jets of Boger fluids and in the presence of gravity effect. In FS process, a fluid jet is forced through an orifice of a rotating spinneret leading to the formation of a curved jet. Applying the upper-convected Maxwell constitutive model for the stress tensor part of the governing non-Newtonian jet system and using
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Emerging, ripening, and attenuating stages of granular roll waves J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-09 Jianbo Fei; Yuxin Jie; Zezhou Wu; Min Zhu
Adopting the form of the dynamic μ(Fr,h) basal friction law and introducing a second-order viscous term into the Saint Venant-type equations, we simulated two-dimensional granular roll waves generated in a rectangular chute applying the second-order-accurate total-variation-diminishing MacCormack scheme. Consistent with previous findings, we found that the amplitude and wavelength of the wave increased
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Viscoplastic dam-breaks J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-11-18 R. Valette; A. Pereira; S. Riber; L. Sardo; A. Larcher; E. Hachem
We analyse through numerical simulations, experiments, and scaling laws the dam-break problem for viscoplastic materials. Numerically, both two and three-dimensional (2D and 3D) scenarios are considered thanks to a proposed adaptive stabilized finite element framework able to compute efficiently free surface flows of highly viscoplastic materials. We choose to focus on the Bingham model. Momentum and
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A novel suspension transport method: Viscoplastic lubrication of high-density fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-11-21 S. Garmeh; A. Dolatabadi; I. Karimfazli
We present proof-of-concept experiments to illustrate the application of viscoplastic lubrication in transport of high-concentration suspensions. The proposed transport method appears robust for a wide range of suspension concentrations. We develop a theoretical description of the flow that incorporates the significant density difference between the suspension and the lubricating fluid. We explore
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Non-Newtonian fluid flow through a sudden pipe contraction under non-isothermal conditions J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-11-10 K.E. Ryltseva; E.I. Borzenko; G.R. Shrager
A steady-state laminar flow of a viscoplastic fluid through an axisymmetric sudden pipe contraction under non-isothermal conditions has been studied numerically. Mathematical formulation of the problem is given using stream function – vorticity – temperature variables. Rheological properties of the fluid are described by the Herschel–Bulkley model, which implies an unyielded region formation in the
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The Tensor Diffusion approach for simulating viscoelastic fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-27 Patrick Westervoß; Stefan Turek; Hogenrich Damanik; Abderrahim Ouazzi
In this paper, the novel Tensor Diffusion approach for the numerical simulation of viscoelastic fluids is introduced based on the idea, that the extra-stress tensor in the momentum equation of the flow model can be replaced by the product of the strain-rate tensor and a (nonsymmetric) tensor-valued viscosity. As potential advantage (which can be demonstrated for fully developed channel, resp., pipe
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Benchmark solutions for flows with rheologically complex interfaces J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-29 M.A. Carrozza; M.A. Hulsen; P.D. Anderson
Complex fluid–fluid interfaces determine for a large part the macroscopic material properties of foams and emulsions that appear in applications such as food, materials processing and consumer care products. As a step towards predicting these properties, a 2D axisymmetric and a 3D finite element model have been developed for simulating the dynamics of a single Newtonian drop in a Newtonian matrix fluid
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Influence of physical and rheological properties of sweeping fluids on the residual oil saturation at the micro- and macroscale J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-11-07 P. Druetta; F. Picchioni
Oil recovery processes depend on many factors that can be altered in order to maximize the sweeping efficiency in porous media, and one of these is the rheology behavior of the displacing agent. Furthermore, scales in the recovery process should also be considered: from the macro- to microscale systems, in which capillary forces become predominant. It is also well-known the non-Newtonian behavior of
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Dynamics of viscoelastic flow through axisymmetric constricted microcapillary at high elasticity number J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-28 J.A.F. Gutiérrez; M.J.B. Moura; M.S. Carvalho
The fundamental understanding of pore scale flow mechanisms associated with the mobilization of trapped oil ganglia during the injection of polymer solutions in porous media requires detailed analysis of viscoelastic flow through pore throats, which can be modeled as constricted capillaries. Despite the vast literature on macroscale and, more recently, microscale viscoelastic flow through contraction–expansion
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Dean flow of a Bingham fluid in a curved rectangular duct J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-11-02 Miguel Moyers-Gonzalez; Ian A. Frigaard
In this paper we study the flow of a Bingham fluid on a curved (rectangular) pipe. Flows in this kind of geometries present secondary flows due to presence of centripetal forces in the radial direction. This so called Dean Flow has been extensively studied for Newtonian fluids. In considering a yield stress fluid in similar geometries the picture is less clear. Unfortunately, there is not an analytical
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Rheological analysis of natural and diluted mud suspensions J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-31 Ahmad Shakeel; Alex Kirichek; Claire Chassagne
Natural mud usually exhibits non-Newtonian rheological behaviors like viscoelasticity, thixotropy and yield stress. The history of each mud sample is also an important factor influencing the rheological behavior, as the state of the clay fabric – for a same composition – is dependent on the shear stresses experienced previously by the sample. Several rheological tests including stress ramp-up, oscillatory
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Rheology of graphene oxide suspended in yield stress fluid J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-21 Lorena R.da C. Moraes; Hélio Ribeiro; Elyff Cargnin; Ricardo Jorge E. Andrade; Mônica F. Naccache
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Oscillatory Rayleigh–Bénard Convection in elasto-viscoplastic gels J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-23 Christel Métivier; Frédéric Brochard; Mohamed Darbouli; Albert Magnin
Rayleigh–Bénard convection (RBC) is studied in an elasto-viscoplastic (EVP) gel, the widely used and studied Carbopol gel. The transition from conductive to convective regime is determined by the Schmidt–Milverton principle which leads to a critical value of the inverse of the Yield number 1∕Yc. However, an oscillatory motion in the gel is observed below 1∕Yc≈60 when smooth and untreated walls are
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Flow classification of radial and squeeze flows between parallel disks J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-19 Jang Min Park
The flow classification developed by Thompson and Souza Mendes [Int. J. Engng. Sci. 43 (2005) 79-105] is applied to radial and squeeze flows between two parallel disks. Based on the lubrication approximation, explicit expressions of the flow classification parameter, namely ℛ, could be obtained for those flows, and the results for power-law and Bingham fluids are presented. It is shown that 0≤ℛ≤1 in
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Annular Couette–Poiseuille flow and heat transfer of a power-law fluid – analytical solutions J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-18 Sharat V. Chandrasekhar
Analytical solutions involving hypergeometric functions are presented for the fully developed laminar flow of a Non-Newtonian fluid in an annulus with a stationary or a moving inner boundary. The solutions are valid for arbitrary values of the power law index in the Couette–Poiseuille flow under consideration, and consider scenarios with and without extrema in the velocity profile, in addition to flow
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A comparison of constitutive models for describing the flow of uncured styrene-butadiene rubber J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-19 Martin Řehoř; Alex Gansen; Clemens Sill; Patrycja Polińska; Stephan Westermann; Jean Dheur; Jörg Baller; Jack S. Hale
Uncured styrene-butadiene rubber (SBR) can be modelled as a viscoelastic material with at least two different relaxation mechanisms. In this paper we compare multi-mode constitutive models combining two viscoelastic modes (linear and/or nonlinear) in three possible ways. Our particular choice of the two modes was inspired by models originally developed to describe the response of asphalt binders. We
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Rheological modifiers in drilling fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-19 Roberta K. Rodrigues; Stephanie de F.C. Martins; Monica F. Naccache; Paulo R. de Souza Mendes
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Viscoelastic flow-induced oscillations of a cantilevered beam in the crossflow of a wormlike micelle solution J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-21 Anita A. Dey; Yahya Modarres-Sadeghi; Jonathan P. Rothstein
We investigate the interactions between a cantilevered flexible beam and cross-flow of a viscoelastic fluid. Unlike Newtonian fluids, viscoelastic fluids exhibit elastic flow instabilities even in the absence of inertia. These elastic flow instabilities drive the oscillations of flexible structures placed in their flow path. In this work, the fluid–structure interactions between the flow of viscoelastic
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Lattice Boltzmann method for viscoplastic fluid flow based on regularization of ghost moments J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-09 Alan Lugarini; Admilson T. Franco; Paulo C. Philippi
In the Lattice Boltzmann Method (LBM) the viscosity is inversely proportional to the relaxation frequency. Hence, it should be possible to represent the singularity of some viscoplastic models by setting the relaxation frequency to zero. In the present paper we take full advantage of the LBM capabilities to propose an efficient and stable numerical scheme for viscoplastic fluid flow simulations invoking
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Rheology of a dilute suspension of Brownian thin disklike particles in a turbulent channel flow J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-10-09 Amin Moosaie; Zahra Zarghami-Dehaghani; Zohreh Alinejad
The orientation distribution of tiny Brownian oblate spheroidal particles suspended in a turbulent channel flow along with their generated non-Newtonian stresses are studied numerically. The direct numerical simulation of turbulent channel flow is coupled with a direct Monte-Carlo simulator for the particles conformation. The effects of particle shape factor and the intensity of rotary Brownian motion
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Haemodynamics around confined microscopic cylinders J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-25 T. Rodrigues; F.J. Galindo-Rosales; L. Campo-Deaño
Motivated by the recent developments in the research of untethered microrobots for performing minimally invasive procedures inside blood vessels, we have devised a novel microfluidic experiment for studying the haemodynamics around different types of cylinders confined inside a straight, long, 270×100μm channel. Two test sections are studied: flow past a confined circular cylinder and past a confined
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Inertia-driven and elastoinertial viscoelastic turbulent channel flow simulated with a hybrid pseudo-spectral/finite-difference numerical scheme J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-28 Lu Zhu; Li Xi
Numerical simulation of viscoelastic flows is challenging because of the hyperbolic nature of viscoelastic constitutive equations. Despite their superior accuracy and efficiency, pseudo-spectral methods require the introduction of artificial diffusion (AD) for numerical stability in hyperbolic problems, which alters the physical nature of the system. This study presents a hybrid numerical procedure
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Large eddy simulation of turbulent pulp flow in a channel J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-28 Nima Fallah Jouybari; Birgitta Engberg; Johan Persson
Large eddy simulation (LES) of turbulent flow of concentrated fiber suspension or pulp is carried out to investigate the flow and turbulence structures in a channel. The simulations are carried out for the turbulent flow of Eucalyptus pulp suspension using OpenFOAM for three fiber concentrations (c = 1.5, 2.0 and 2.5) and six different Reynolds numbers (6 ≤Res≤ 16,600). It is observed that the variation
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Dynamics and deformation of a three-dimensional bubble rising in viscoelastic fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-28 Wenjun Yuan; Mengqi Zhang; Boo Cheong Khoo; Nhan Phan-Thien
The rise of a deforming air bubble of fixed volume surrounded by viscoelastic liquids is investigated by an adaptive direct numerical technique coupled with the volume-of-fluid method. The effects of the Weissenberg number (characterizing the strength of elasticity in the flow) and the viscosity ratio on the three-dimensional bubble dynamics have been studied and identified in a wide range of Galilei
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Analysis of the flow between parallel coaxial discs with relative axial motion and rotation J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-24 Roney Leon Thompson; Paulo R. de Souza Mendes
This paper addresses the rheometrical flow that combines squeezing and rotating between coaxial parallel discs. Experimental results obtained with this flow have been used as evidence that the von Mises criterion holds for the materials tested. In fact, these results are frequently referred to as a proof of the validity of the von Mises criterion. However, the detailed analysis described here shows
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Waxy oils: Deformation-dependent materials J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-22 Amanda Legnani; Tainan G.M. Santos; Diogo E.V. Andrade; Cezar O.R. Negrão
Waxy oils are thermal and shear dependent materials as the initial and final cooling temperatures, cooling rate, shear rate applied during the cooling and the aging time affect the rheological properties of the material. As reported in recent papers, the waxy oil equilibrium flow curve is not only a function of thermal and shear histories but also of the maximum shear rate imposed on the sample. In
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Flow of a Bingham fluid in a pipe of variable radius J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-19 Lorenzo Fusi; Kostas D. Housiadas; Georgios C. Georgiou
We extend a method developed by Fusi and Farina (Appl. Math. Comp. 320, 1–15, 2018) to obtain semi-analytical lubrication-approximation solutions for the flow of a Bingham-plastic in a tube of variable radius. The proposed method is applicable provided that the unyielded core extends continuously from the inlet to the outlet. It turns out that the variable radius of the latter core obeys a stiff integral-algebraic
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A fast numerical scheme for the Poiseuille flow in a concentric annulus J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-19 Raja R. Huilgol; Georgios C. Georgiou
A fast numerical scheme is proposed to determine the velocity field of an incompressible fluid in a concentric annulus under a constant pressure gradient. The idea behind the scheme is to find the radius R in the annulus where the shear stress becomes zero. In the region from the inner wall at R=κ to R, the shear rate is positive, while it is negative from this radius to the outer wall at r=1. Integrating
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Rheology modulated high electrochemomechanical energy conversion in soft narrow-fluidic channel J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-27 Harshad Sanjay Gaikwad; Pranab Kumar Mondal
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Linear instability driven by an electric field in two-layer channel flow of Newtonian and Herschel–Bulkley fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-18 K. Gautam; P.A.L. Narayana; Kirti Chandra Sahu
We investigate the linear stability characteristics of a pressure-driven two-layer channel flow of immiscible Newtonian and Herschel–Bulkley fluids subjected to an applied electric field normal to the flow. The linear stability equations are derived and solved using an accurate spectral Chebyshev collocation method. It is found that the electric field can stabilise or destabilise the flow depending
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Viscometric functions and rheo-optical properties of dilute polymer solutions: Comparison of FENE-Fraenkel dumbbells with rodlike models J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-09 I. Pincus; A. Rodger; J. Ravi Prakash
Rigid macromolecules or polymer chains with persistence length on the order of the contour length (or greater) have traditionally been modelled as rods or very stiff springs. The FENE-Fraenkel-spring dumbbell, which is finitely extensible about a non-zero natural length with tunable harmonic stiffness, is one such model which has previously been shown to reproduce bead–rod behaviour in the absence
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The flow of power-law fluids in concentric annuli: A full analytical approximate solution J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-08 Rémi Deterre; François Nicoleau; Qiao Lin; Nadine Allanic; Pierre Mousseau
This work deals with the zero shear rate (maximum velocity) position parameter λ of a steady laminar axial annular flow of power-law fluids especially polymeric ones. λ is involved in the shear rate, velocity profile and the flow rate calculations, which are essential for studies such as viscous dissipation, convective heat transfer and pressure drop prediction in annuli. However, the analytical explicit
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Complex flows of viscoelastic wormlike micelle solutions J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-01 Jonathan P. Rothstein; Hadi Mohammadigoushki
Micelles are formed by the self-assembly of surfactants in solutions. Wormlike micelles or living polymers are a particularly interesting fluids because their long flexible cylindrical geometry can lead to entanglement even at relatively low concentrations. The rheological response of the wormlike micelles is similar in many ways to polymer solutions. Entangled wormlike micelles provide a model fluid
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Vortex deformation and turbulent energy of polymer solution in a two-dimensional turbulent flow J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-04 Ruri Hidema; Kengo Fukushima; Ryohei Yoshida; Hiroshi Suzuki
An experimental study was performed to investigate the effects of the extensional rheological properties of polymer solutions on vortex deformation in turbulent flow and turbulent statistics. To focus on the extensional properties, a self-standing two-dimensional (2D) turbulent flow was used as an experimental setup, and the flow was observed through interference patterns and particle image velocimetry
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Numerical simulation of blood flow modeled as a fluid- particulate mixture J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-09-01 Krishna Chandran, Indranil Saha Dalal, Kazuya Tatsumi, Krishnamurthy Muralidhar
A continuum model for the transport of red blood cells (RBC) inside arteries and capillaries of small diameters is proposed. The pressure and velocity fields are solved using the Navier-Stokes equations while the distribution of the RBC volume fraction, namely, hematocrit is obtained by solving the particle transport equation arising from the diffusive flux model. The momentum and hematocrit transport
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A BDF2-semismooth Newton algorithm for the numerical solution of the Bingham flow with temperature dependent parameters J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-27 Sergio González-Andrade
This paper is devoted to the numerical solution of the non-isothermal instationary Bingham flow with temperature dependent parameters by semismooth Newton methods. We discuss the main theoretical aspects regarding this problem. Mainly, we discuss the existence of solutions for the problem, and focus on a multiplier formulation which leads us to a coupled system of PDEs involving a Navier–Stokes type
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Particle migration in channel flow of an elastoviscoplastic fluid J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-22 Emad Chaparian, Mehdi N. Ardekani, Luca Brandt, Outi Tammisola
We study the dynamics of a neutrally buoyant rigid sphere carried by an elastoviscoplastic fluid in a pressure-driven channel flow numerically. The yielding to flow is marked by the yield stress which splits the flow into two main regions: the core unyielded region and two sheared yielded regions close to the walls. The particles which are initially in the plug region are observed to translate with
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Computing the yield limit in three-dimensional flows of a yield stress fluid about a settling particle J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-20 José A. Iglesias, Gwenael Mercier, Emad Chaparian, Ian A. Frigaard
Calculating the yield limit Yc (the critical ratio of the yield stress to the driving stress), of a viscoplastic fluid flow is a challenging problem, often needing iteration in the rheological parameters to approach this limit, as well as accurate computations that account properly for the yield stress and potentially adaptive meshing. For particle settling flows, in recent years calculating Yc has
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Restart behavior of gelled waxy crude oil pipeline based on an elasto-viscoplastic thixotropic model: A numerical study J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-20 Youquan Bao, Jinjun Zhang
Restart of gelled waxy crude oil pipeline is one of the major flow assurance concern in petroleum production. Reliable representation of rheological behavior of gelled waxy crude oil serves as the basis for pipeline restart analysis and modeling. In this work, the Dullaert-Mewis elasto-viscoplastic thixotropic model was modified and applied to improve the representation of the rheology of gelled waxy
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Axisymmetric flow simulations of fiber suspensions as described by 3D probability distribution function J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-18 Julien Férec, Dihya Mezi, Suresh G. Advani, Gilles Ausias
Numerical models are developed to examine fiber suspension flows through axisymmetric geometries, such as a circular pipe, a center-gated disk and a die exit. The fiber orientation micro-structure is fully described by using the entire probability distribution function (PDF) in 3D instead of the second and fourth moments of the PDF, which introduce errors due to the closure approximation when using
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Simple criterion for vortex formation in the channel flow of power-law fluids J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-15 Hyungyeol Kwak, Jaewook Nam
Vortices can have negative effects on the processing of various flows in industrial engineering. Thus, there have been many attempts to seek vortex-free operating conditions. This study explores the feasibility of applying the flow reversal condition in the Couette–Poiseuille (C–P) flow of power-law fluid to the prediction of vortex birth. In previous studies, flow reversal conditions are explicitly
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Dynamics of viscoplastic filament stretching J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-11 Pantelis Moschopoulos, Alexandros Syrakos, Yannis Dimakopoulos, John Tsamopoulos
We use numerical simulations to study the stretching and pinching of a viscoplastic material that is confined by two coaxial disks when they are pulled apart. The material initially forms a cylindrical bridge between the disks, follows the Heschel-Bulkley model and yields according to the von Mises criterion. We solve the governing equations numerically in their 2D, axisymmetric form using the PAL
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Bulk and interfacial modes of instability in channel flow of thixotropic-viscoelasto-plastic fluids with shear-banding J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-11 Hugo A. Castillo, Helen J. Wilson
We carry out a linear stability analysis of the generalised BMP model, which incorporates the shear-banding phenomenon into flows of thixotropic-viscoelasto-plastic fluids: common behaviours observed in wormlike micellar solutions. We introduce a new dimensionless parameter governing shear-banding, and find that when a flow is unstable in the absence of shear-banding, this parameter has a stabilising
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A viscoelastic two-phase solver using a phase-field approach J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-08 Konstantinos Zografos, Alexandre M. Afonso, Robert J. Poole, Mónica S.N. Oliveira
In this work we discuss the implementation and the performance of an in-house viscoelastic two-phase solver, based on a diffuse interface approach. The Phase-Field method is considered and the Cahn-Hilliard equation is employed for describing the transport of a binary fluid system. The interface between the two fluids utilises a continuum approach, which is responsible for smoothing the inherent discontinuities
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PEGAFEM-V: A new petrov-galerkin finite element method for free surface viscoelastic flows J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-08-07 S. Varchanis, A. Syrakos, Y. Dimakopoulos, J. Tsamopoulos
The recently proposed finite element (FE) formulation for viscoelastic flows that allows the use of equal order linear interpolants for all variables and simultaneously does not suffer from the high Weissenberg number problem, is extended to free surface flows. The coupling of this Petrov-Galerkin stabilized FE formulation with the quasi-elliptic mesh generator allows us to obtain stable numerical
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Retraction criteria of viscoplastic drops and sheets: Long-wave approximations J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-07-25 Hiranya Deka, Jean-Lou Pierson, Edson J. Soares
Retraction dynamics of viscous drops and sheets depend on the relative magnitude of the viscous force over the inertia-capillary force. The dynamics are more complicated in the case of viscoplastic drops/sheets because the yield stress of the fluid also comes into play. The retraction of slender viscoplastic drops and sheets depends on the relative magnitude of the yield stress over the capillary stress
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Interaction between a falling sphere and the structure of a non-Newtonian yield-stress fluid J. Non-Newtonian Fluid Mech. (IF 2.538) Pub Date : 2020-07-25 Nicolò R. Sgreva, Anne Davaille, Ichiro Kumagai, Kei Kurita
We present an experimental study using mixtures of aqueous superabsorbent polymers (SAP) where we systematically investigate the influence of the size of grains that make up the fluid structure on the mixture effective rheology and its domain of validity. In water, SAP powder grains can swell up to 200 times and form gel grains, dg, whose sizes (typically between 1 and 8 mm) can be controlled by choosing