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Apparent wall slip effects on rheometric measurements of waxy gels J. Rheol. (IF 3.711) Pub Date : 2021-02-25 Thiago O. Marinho; Flávio H. Marchesini; Márcia C. K. de Oliveira; Márcio Nele
The effects of apparent wall slip on rheometric measurements of waxy gels are quantified for gels consisting of a macrocrystalline wax added in mineral oil in concentrations of 3.0 and 7.5 wt. %. The waxy gels are formed in situ in a stress-controlled rheometer, and rheological properties are then obtained. Seven different geometry configurations, including parallel plates, concentric cylinders, and
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Transient dynamics of soft particle glasses in startup shear flow. Part I: Microstructure and time scales J. Rheol. (IF 3.711) Pub Date : 2021-02-22 Fardin Khabaz; Bruno Flavio Di Dio; Michel Cloitre; Roger T. Bonnecaze
The rheology and microstructure of soft particle glasses during startup flow are studied using three-dimensional particle dynamics simulations at different particle volume fractions and shear rates. The behavior of transient stress depends on the applied shear rate. At high shear rates, soft particle glasses exhibit a static yield stress signaled by a stress overshoot followed by a relaxation to a
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Yield stress behavior of colloidal gels with embedded active particles J. Rheol. (IF 3.711) Pub Date : 2021-02-19 Keara T. Saud; Mahesh Ganesan; Michael J. Solomon
The yield stress behavior of colloidal gels with embedded active particles is studied with three experiments: start-up of steady shear, oscillatory strain amplitude sweep, and creep testing. Activity is generated by Janus particles with a platinum hemisphere; these particles undergo self-diffusiophoretic and self-electrophoretic motion in hydrogen peroxide solutions. The free particle active motion
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Wall slip in primitive chain network simulations of shear startup of entangled polymers and its effect on the shear stress undershoot J. Rheol. (IF 3.711) Pub Date : 2021-02-19 Yuichi Masubuchi; Dimitris Vlassopoulos; Giovanni Ianniruberto; Giuseppe Marrucci
In some recent experiments on entangled polymers of stress growth in the startup of fast shear flows, an undershoot in the shear stress is observed following the overshoot, i.e., before approaching the steady state. Whereas tumbling of the entangled chain was proposed to be at its origin, here, we investigate another possible cause for the stress undershoot, i.e., slippage at the interface between
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Wall slip and bulk yielding in soft particle suspensions J. Rheol. (IF 3.711) Pub Date : 2021-02-12 Gerhard Jung; Suzanne M. Fielding
We simulate a dense athermal suspension of soft particles sheared between hard walls of a prescribed roughness profile, fully accounting for the fluid mechanics of the solvent between the particles and for the solid mechanics of changes in the particle shapes. We, thus, capture the widely observed rheological phenomenon of wall slip. For imposed stresses below the material’s bulk yield stress, we show
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Data-driven physics-informed constitutive metamodeling of complex fluids: A multifidelity neural network (MFNN) framework J. Rheol. (IF 3.711) Pub Date : 2021-02-11 Mohammadamin Mahmoudabadbozchelou; Marco Caggioni; Setareh Shahsavari; William H. Hartt; George Em Karniadakis; Safa Jamali
In this work, we introduce a comprehensive machine-learning algorithm, namely, a multifidelity neural network (MFNN) architecture for data-driven constitutive metamodeling of complex fluids. The physics-based neural networks developed here are informed by the underlying rheological constitutive models through the synthetic generation of low-fidelity model-based data points. The performance of these
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Rheological and thermal properties of the KF-KCl-K2SiF6 electrolyte for electrolytic production of silicon J. Rheol. (IF 3.711) Pub Date : 2021-02-05 Andrey Isakov; Anastasia Khudorozhkova; Alexander Redkin; Yurii Zaikov
Viscosity and phase transitions were studied in the (KF-KCl)eut.-(10 mol. %)K2SiF6 system. Synchronous thermal analysis (STA) was used to study the phase transformations in the system in the temperature range of 298–1113 K. The (KF-KCl)eut.-(10 mol. %)K2SiF6 melt was found to be homogeneous at 903–993 K. The viscosity of the system under study was investigated by the rotational viscometer FRS 1600
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Buffered λ-DNA solutions at high shear rates J. Rheol. (IF 3.711) Pub Date : 2021-02-04 H. Dakhil; S. K. Basu; S. Steiner; Y. Gerlach; A. Soller; Sharadwata Pan; Natalie Germann; M. Leidenberger; B. Kappes; A. Wierschem
We study buffered aqueous solutions of deoxyribonucleic acid isolated from bacteriophage lambda (λ-DNA) at shear rates up to 105 s−1. The shear rates are accessed with a narrow-gap rheometer at gap widths down to 20 μm. At lower shear rates, our data merge with the literature values. At high shear rates, the viscosity levels off into an infinite-shear viscosity plateau. Hence, the viscosity functions
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Direct measurements of the microstructural origin of shear-thinning in carbon black suspensions J. Rheol. (IF 3.711) Pub Date : 2021-01-29 Julie B. Hipp; Jeffrey J. Richards; Norman J. Wagner
Scientific questions surrounding the shear-dependent microstructure of carbon black suspensions are motivated by a desire to predict and control complex rheological and electrical properties encountered under shear. In this work, direct structural measurements over a hierarchy of length scales spanning from nanometers to tens of micrometers are used to determine the microstructural origin of the suspension
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Revisiting the basis of transient rheological material functions: Insights from recoverable strain measurements J. Rheol. (IF 3.711) Pub Date : 2021-01-27 Piyush K. Singh; Johnny Ching-Wei Lee; Kshitish A. Patankar; Simon A. Rogers
Recent studies have shown that rheological material functions that can be linked to structural measures are defined in terms of the recoverable and unrecoverable strains [for example, Lee et al., Phys. Rev. Lett. 122, 248003 (2019)]. In this study, we explore the consequences of applying these ideas to transient nonlinear rheological tests, using new material functions including an elastic modulus
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An orientation-stretch coupled model for entangled comb polymers J. Rheol. (IF 3.711) Pub Date : 2021-01-22 Zhongqiang Xiong; Wei Yu
A semi-empirical constitutive equation is suggested for the model comb polymer with the purpose to simultaneously describe the intrinsic medium amplitude oscillatory shear (MAOS) behaviors and transient behaviors in start-up elongational experiments. The molecular stress and hierarchical relaxation of comb polymers are discussed on the basis of the orientation-stretch coupled conformation tensor of
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Electrorheological behaviors of waxy crude oil gel J. Rheol. (IF 3.711) Pub Date : 2021-01-11 Qian Huang; Hongying Li; Yiwei Xie; Yifei Ding; Yu Zhuang; Chaohui Chen; Shanpeng Han; Jinjun Zhang
The paraffin molecules in crude oil crystalize and precipitate out as the oil cools, resulting in a sharp increase in oil viscosity and further the gelation of the oil. The waxy crude oil gel exhibits complex rheological behaviors, such as viscoelasticity, yield stress, and thixotropy, posing challenges to the flow assurance of pipelines. Previous studies have verified that applying a high-voltage
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Solubility, dissolution thermodynamics and preferential solvation of 4-nitroaniline in (ethanol + water) mixtures Phys. Chem. Liq. (IF 1.707) Pub Date : 2021-02-28 Sema Akay; Berkant Kayan; Fleming Martínez
ABSTRACT In this research, the equilibrium mole fraction solubility of 4-nitroaniline (4-NA) in some aqueous-ethanolic mixtures was determined at seven temperatures from (293.15 to 323.15) K. The respective apparent thermodynamic functions (Gibbs energy, enthalpy, and entropy) of the dissolution processes were computed using the van’t Hoff and Gibbs equations. The enthalpy-entropy relationship for
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‘H-states’: exact solutions for a rotating hollow vortex J. Fluid Mech. (IF 3.354) Pub Date : 2021-03-01 D.G. Crowdy; R.B. Nelson; V.S. Krishnamurthy
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Flow past a circular cylinder and a downstream sphere for Re < 300 J. Fluid Mech. (IF 3.354) Pub Date : 2021-03-01 Ming Zhao
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Prediction of shear thickening of particle suspensions in viscoelastic fluids by direct numerical simulation J. Fluid Mech. (IF 3.354) Pub Date : 2021-03-01 Yuki Matsuoka; Yasuya Nakayama; Toshihisa Kajiwara
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Magnetization AC losses of iron-based Ba-122 superconducting tapes Cryogenics (IF 1.818) Pub Date : 2021-03-01 J. Kováč; M. Kapolka; P. Kováč; L. Kopera; E. Pardo; Y.C. Zhu; C. Yao; D.L. Wang; Y.W. Ma
Magnetization AC loss measurements of singe- and seven-core Ba122/Ag tapes have been done by calibration-free method in the range of temperature from 20 K to 42 K and field magnitudes up to 70 mT in RMS with two frequencies 72Hz and 144Hz. A strong effect of eddy current losses in highly conductive Ag sheath was observed for single-core sample, but negligible for seven-core tape with more resistive
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Investigation on the thermal performance of spiral wound heat exchanger for the superfluid helium cryogenic system Cryogenics (IF 1.818) Pub Date : 2021-03-01 Jun Zhang; Chen-chen Song; Xiao-fei Niu; Xian-jin Wang; Feng Bai; Hai-lin Bi
Spiral wound heat exchanger has compact structure, good thermal performance per volume and simple manufacture process. It is the key equipment for the superfluid helium cryogenic system, which is able to recover the cold capacity and improve the refrigeration effectiveness. To investigate the influence of fins structure on the thermal performance of spiral wound heat exchanger is essential for its
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Exergetic analysis of reverse Brayton cryocooler with different turbine arrangements for HTS power cables Cryogenics (IF 1.818) Pub Date : 2021-03-01 Aman Kumar Dhillon; Parthasarathi Ghosh
The cooling systems of High-Temperature Superconducting (HTS) power transmission cables are unable to achieve the desired performance as prescribed in the cryogenic road map. Reverse Brayton cycle based Cryocooler (RBC) has been identified as a refrigerator that has the potential to achieve the desired performance for higher cooling load demand. In this article, an exergy analysis of the basic Reverse
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Some Explicit Solutions to the Three-Dimensional Nonlinear Water Wave Problem J. Math. Fluid Mech. (IF 0.97) Pub Date : 2021-03-01 Calin I. Martin
We present some explicit solutions (given in Eulerian coordinates) to the three-dimensional nonlinear water wave problem. The velocity field of some of the solutions exhibits a non-constant vorticity vector. An added bonus of the solutions we find is the possibility of incorporating a variable (in time and space) surface pressure which has a radial structure. A special type of radial structure of the
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Existence of a Stationary Navier–Stokes Flow Past a Rigid Body, with Application to Starting Problem in Higher Dimensions J. Math. Fluid Mech. (IF 0.97) Pub Date : 2021-03-01 Tomoki Takahashi
We consider the large time behavior of the Navier–Stokes flow past a rigid body in \(\mathbb {R}^n\) with \(n\ge 3\). We first construct a small stationary solution possessing the optimal summability at spatial infinity, which is the same as that of the Oseen fundamental solution. When the translational velocity of the body gradually increases and is maintained after a certain finite time, we then
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Uniqueness of Dissipative Solutions to the Complete Euler System J. Math. Fluid Mech. (IF 0.97) Pub Date : 2021-03-01 Shyam Sundar Ghoshal; Animesh Jana
Dissipative solutions have recently been studied as a generalized concept for weak solutions of the complete Euler system. Apparently, these are expectations of suitable measure valued solutions. Motivated from Feireisl et al. (Commun Partial Differ Equ 44(12):1285–1298, 2019), we impose a one-sided Lipschitz bound on velocity component as uniqueness criteria for a weak solution in Besov space \(B^{\alpha
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On the Non-diffusive Magneto-Geostrophic Equation J. Math. Fluid Mech. (IF 0.97) Pub Date : 2021-03-01 Daniel Lear
Motivated by an equation arising in magnetohydrodynamics, we address the well-posedness theroy for the non-diffusive magneto-geostrophic equation. Namely, an active scalar equation in which the divergence-free drift velocity is one derivative more singular than the active scalar. In Friedlander and Vicol (Nonlinearity 24(11)::3019–3042, 2011), the authors prove that the non-diffusive equation is ill-posed
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Pullback Attractors for Non-Newtonian Fluids with Shear Dependent Viscosity J. Math. Fluid Mech. (IF 0.97) Pub Date : 2021-03-01 Heraclio Ledgar López-Lázaro; Pedro Marín-Rubio; Gabriela Planas
The so-called Ladyzhenskaya model is analyzed from a non-autonomous dynamical system point of view, for weak and strong solutions. Existence of attractors when forces are time-dependent is ensured in several universes with different tempered parameter conditions, and also for fixed bounded sets. Attraction is proved in \(L^2\) and \(W^{1,p}\) norms and relationships between these families are also
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Dynamics of a droplet driven by an internal active device Phys. Rev. Fluids (IF 2.512) Pub Date : 2021-03-01 R. Kree; L. Rückert; A. Zippelius
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Simulations of multicomponent relativistic thermalization Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 Atul Kedia; Nishanth Sasankan; Grant J. Mathews; Motohiko Kusakabe
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Metastable Potts droplets Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 E. Can Artun; A. Nihat Berker
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Triple point of synchronization, phase singularity, and excitability along the transition between unbounded and bounded phase oscillations in a forced nonlinear oscillator Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 Willian T. Prants; Cristian Bonatto
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Power laws and phase transitions in heterogenous car following with reaction times Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 A. Sai Venkata Ramana; Saif Eddin Jabari
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Master equation analysis of mesoscopic localization in contagion dynamics on higher-order networks Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 Guillaume St-Onge; Vincent Thibeault; Antoine Allard; Louis J. Dubé; Laurent Hébert-Dufresne
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Theory of cell membrane interaction with glass Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 Richard W. Clarke
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Dynamics of laser-generated magnetic fields using long laser pulses Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 Hiroki Morita; Bradley B. Pollock; Clement S. Goyon; Gerald J. Williams; King Fai Farley Law; Shinsuke Fujioka; John D. Moody
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Wrinkling transition in quenched disordered membranes at two loops Phys. Rev. E (IF 2.296) Pub Date : 2021-03-01 O. Coquand; D. Mouhanna
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A geometrically accurate low-diffusive conservative interface capturing method suitable for multimaterial flows Comput. Fluids (IF 2.399) Pub Date : 2021-03-01 Florian De Vuyst; Christophe Fochesato; Vincent Mahy; Renaud Motte; Mathieu Peybernes
This paper is dedicated to the design of an artifact-free and geometrically accurate low-diffusive interface capturing method for pure advection problems with extension to the multifluid/multimaterial case. The numerical method involves a genuinely multidimensional gradient limiting process that provides interface reconstruction accuracy without appearance of usually-encountered artifacts like zigzag-shaped
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Concentrated brines in aqueous methanolic solutions in supercritical conditions: Effect of concentration and composition from molecular dynamics simulations Fluid Phase Equilibr. (IF 2.838) Pub Date : 2021-02-23 Sonanki Keshri; Ujwala N. Patil
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Modeling interfacial properties of ionic liquids with ePC-SAFT combined with density gradient theory Fluid Phase Equilibr. (IF 2.838) Pub Date : 2021-02-23 Yunhao Sun; Zhida Zuo; Gulou Shen; Christoph Held; Xiaohua Lu; Xiaoyan Ji
In this work, ePC-SAFT-DGT (i.e., the coupling of ePC-SAFT with the density gradient theory (DGT)) was further developed by modifying the expression for estimating the chemical potential of IL ion-pair and extended to study the interfacial properties of 82 ionic liquids (ILs) containing one of the IL-cations ([Cnmim]+, [Cnpy]+, [Cnmpy]+, [Cnmpyr]+, and [THTDP]+) and one of the IL-anions ([Tf2N]−, [PF6]−
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Method of self-similar functions for estimating the critical properties of homologous series Fluid Phase Equilibr. (IF 2.838) Pub Date : 2021-02-27 Eugene D. Nikitin; Nataliya S. Bogatishcheva
The coefficients of equations for estimating the critical temperatures, pressures, and densities of homologous series with the general formula R1(CH2)nR2 have been calculated using the current experimental database. The equations are based on the hypothesis of functional self-similarity and the scaling behaviour of the critical constants of long-chain molecules (Nikitin et al. Fluid Phase Equilib.
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New pressure and density based methods for isothermal-isobaric flash calculations Fluid Phase Equilibr. (IF 2.838) Pub Date : 2021-02-27 T. Barath Adhithya; G. Venkatarathnam
Isobaric-isothermal flash calculations are at the heart of any process calculation. In this paper, we propose two new methods for flash calculations at a specified temperature and pressure. The governing equations derived can not only be solved rapidly but also converge correctly even very close to the critical point with the methods presented in this paper. The derived equations show that simplified
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Density and viscosity of CO2 + ethyl acetate binary systems from 308.15 to 338.15 K and 15 to 45 MPa Fluid Phase Equilibr. (IF 2.838) Pub Date : 2021-02-27 Teng Zhu; Houjian Gong; Mingzhe Dong
Combined with a high-pressure vibrating-tube densimeter and capillary viscometer, the density and viscosity of CO2(1)+ethyl acetate(2) binary systems with x2 = 0.000, 0.036, 0.075, 0.117, 0.163, and 1.000 were measured under conditions of 308.15-338.15 K and 15-45 MPa. In addition, the volumes of mixing (ΔVm) and viscosity deviation (Δη) were also calculated. The results illustrate that the density
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Accuracy improvement for directional polarized spectral emissivity measurement in the wavelength range of 4-20 μm Exp. Therm. Fluid Sci. (IF 3.444) Pub Date : 2021-02-27 Longfei Li; Kun Yu; Kaihua Zhang; Yanlei Liu; Feng Zhang; Yufang Liu
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Anisotropic Gaussian random fields: criteria for hitting probabilities and applications Stoch. PDE Anal. Comp. (IF 1.39) Pub Date : 2021-02-27 Adrián Hinojosa-Calleja, Marta Sanz-Solé
We develop criteria for hitting probabilities of anisotropic Gaussian random fields with associated canonical pseudo-metric given by a class of gauge functions. This yields lower and upper bounds in terms of general notions of capacity and Hausdorff measure, respectively, therefore extending the classical estimates with the Bessel–Riesz capacity and the \(\gamma \)-dimensional Hausdorff measure. We
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A regularity theory for stochastic partial differential equations driven by multiplicative space-time white noise with the random fractional Laplacians Stoch. PDE Anal. Comp. (IF 1.39) Pub Date : 2021-02-27 Beom-Seok Han
We present the existence, uniqueness, and regularity of a strong solution to a super-linear stochastic partial differential equation (SPDE) with the random fractional Laplacians: $$\begin{aligned} u_t = a\Delta ^{\alpha /2}u + b u_x + cu + \xi |u|^{1+\lambda } \dot{W},\quad t>0\,;\quad u(0,\cdot ) = u_0(\cdot ), \end{aligned}$$ where \(\dot{W}\) is a space-time white noise, \(\alpha \in (1,2)\), and
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Thermodynamic analysis and preferential solvation of sulfanilamide in different cosolvent mixtures Phys. Chem. Liq. (IF 1.707) Pub Date : 2021-02-26 Claudia Patricia Ortíz; Rossember E. Cardenas-Torres; Diego Ivan Caviedes-Rubio; Sebastian De Jesus Polania-Orozco; Daniel Ricardo Delgado
ABSTRACT The thermodynamic analysis and preferential solvation of the solubility of sulphanilamide (SA) in five cosolvent mixtures (ethanol + water; 1,4-dioxane + water, acetonitrile + water, dimethyl-sulphoxide + water, and dimethylsulphoxide + water) are presented. The thermodynamic functions are calculated employing the Gibbs and van´t Hoff equations, and the analysis of preferential solvation is
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Layer-adapted meshes for solute dispersion in a steady flow through an annulus with wall absorption: Application to a catheterized artery Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2021-02-27 Nanda Poddar, Kajal Kumar Mondal, Niall Madden
This paper describes the longitudinal dispersion of passive tracer molecules injected in a steady, fully developed, viscous, incompressible, laminar flow through an annular pipe with a first order heterogeneous boundary absorption at the outer wall, numerically using layer-adapted meshes. The model is based on steady advection-diffusion equation with Dirichlet and Robin boundary conditions. The solutions
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Non-Newtonian Casson pulsatile fluid flow influenced by Lorentz force in a porous channel with multiple constrictions: A numerical study Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2021-02-27 Amjad Ali, Attia Fatima, Zainab Bukhari, Hamayun Farooq, Zaheer Abbas
In this paper, we investigate non-Newtonian Casson fluid flow with pulsation in a channel having symmetrical constriction bumps on the upper and lower walls. The medium is assumed to be porous, following Darcy’s law. The fluid is modeled as electrically low conducting, and the pulsatile flow is subjected to a transverse magnetic field of uniform strength to study the impact of the resulting Lorentz
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Structure-rheology elucidation of human blood via SPP framework and TEVP modeling Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2021-02-27 Matthew Armstrong, Jeff Baker, Jesse Trump, Erin Milner, J. Kenneth Wickiser, Kenneth Cameron, Nick Clark, Kaitlyn Schwarting, Thomas Brown, Dorian Bailey, Corey James, Chi Nguyen, Trevor Corrigan
Recent work modeling the rheological behavior of human blood indicates that it has all the hallmark features of a complex material, including shear-thinning, viscoelastic behavior, a yield stress, and thixotropy. After decades of modeling steady state blood data, and the development of simple steady state models, like the Casson and Herschel-Bulkley the advancement and evolution of blood modeling to
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Characterization of polyethylene/silica nanocomposites using different rheological analyses Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2021-02-27 Mingeun Kim, Kyu Hyun
Polyethylene (PE)/silica polymer nanocomposites (PNCs) were investigated mainly using rheological measurements. Various PEs [linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and low-density polyethylene (LDPE)] were selected as polymer matrices, and two comparable particulate silicas were utilized as favorable (hydrophobic, R202) or unfavorable (hydrophilic, A90) fillers.
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Calculation of molecular weight distribution using extended Cole-Cole model and quadratic mixing rule Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2021-02-27 Junghaeng Lee, Sangmo Kim, Kwang Soo Cho
We suggest a numerical method to calculate molecular weight distribution from linear viscoelastic data. The calculation method consists of three components: (1) a viscoelastic model of a monodisperse polymer as a function of molecular weight; (2) the mixing rule connecting viscoelastic data of monodisperse and polydisperse polymers through molecular weight distribution; (3) an algorithm which calculates
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Viscoelastic characterization of the mucus from the skin of loach Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2021-02-27 Shuxin Huang
The epidermal mucus secreted by fish is a natural barrier between fish and water, which is a slippery and slightly thick fluid with some biological functions. The present work is to characterize the viscoelastic property of a loach skin mucus published recently by using a viscoelastic model with four hypotheses. The experimental steady shear viscosity with the maximum shear rate of 10 s−1 for the mucus
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Effect of isocyanate crosslinkers blocked with amine derivatives on rheological and crosslinking characteristics of automotive clearcoats Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2021-02-27 Young-Gun June, Kevin Injoe Jung, Tae Hee Lee, Miran Ha, Seung Man Noh, Hyun Wook Jung
Isocyanate crosslinkers with blocking agents based on various amine derivatives were newly synthesized for automotive clearcoat applications. Amine-based blocking agents were prepared by varying the alkyl substituent attached on both sides of the main nitrogen atom (named DEA, DiPA, NtBEA, and NtBiA) to modify their deblocking feature in blocked isocyanates (BIs) and curing reaction under thermal curing
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Experimental Study on the Effect of Gas Adsorption on the Effective Stress of Coal Under Triaxial Stress Transp Porous Media (IF 2.376) Pub Date : 2021-02-27 Zhaoxing Lv, Peng Liu, Yangsheng Zhao
The deformation of coal during the injection of sorptive gases can be classified into two types: deformation due to the pore pressure and the swelling deformation of the coal matrix induced by adsorption. These types of deformation have not been investigated separately in the previous researches. The main reason is that measuring the radial strain of the coal core directly and accurately is extremely
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Transverse FIV suppression of square cylinder using two control rods of varying size and distance in lock-in and galloping regions Int. J. Numer. Methods Heat Fluid Flow (IF 2.871) Pub Date : 2021-03-01 S. D. Farahani; Amir Hossein Rabiee
Purpose) In this study, for the first time, the efficacy of control rods for full suppression of vortex-induced vibrations (VIV) and galloping of an elastically supported rigid square cylinder that vibrates freely in the cross-flow direction is investigated. Design/methodology/approach To this aim, two small control rods are placed at constant angles of ± 45° relative to the horizontal axis and then
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Hydrodynamics of Euglena Gracilis during locomotion J. Hydrodyn. (IF 2.265) Pub Date : 2021-02-24 Fahrettin Gökhan Ergin
The hydrodynamics and locomotion mechanism of Euglena Gracilis (E. Gracilis) is investigated using microscopic shadow imaging and micro particle image velocimetry (MicroPIV). Three distinct locomotion modes were observed: translation, spin, and left/right turn. Since the flagellum was not possible to image, the strokes were identified by evaluating the flow field around the protist. The flow field
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Statistical Characterization of Flow Structure of Air–water Two-phase Flow in Airlift Pump–Bubble Generator System Int. J. Multiphase Flow (IF 3.083) Pub Date : 2021-02-17 IGNB. Catrawedarma; Deendarlianto; Indarto
The aim of this study is to identify the flow structure in an airlift pump–bubble generator system by using experimentally obtained differential pressure signals. Differential pressure measurements were applied at both the bottom and top test sections. The normalized time variation of the differential pressure data was analyzed using the probability density function (PDF), power spectral density function
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Beyond time-averaged measurement of bubble parameters in steam-water flows with conductivity probes Int. J. Multiphase Flow (IF 3.083) Pub Date : 2021-02-13 Zhiee Jhia Ooi; Caleb S. Brooks
Two-phase data from flashing experiments are presented beyond the traditional time-averaged approach in this work. Probability density functions of parameters such as bubble duration, velocity, chord length, and number frequency are obtained from four-sensor conductivity probes and presented here. The axial evolution of the distributions is discussed in detail along with high-speed videos for a qualitative
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Gas-liquid two-phase flow patterns in the wake of a submerged nozzle under co-flow condition Int. J. Multiphase Flow (IF 3.083) Pub Date : 2021-02-17 Ning Mao; Can Kang; Kejin Ding; Qian Cao
The present study aims to reveal gas-liquid flow patterns as gas is injected into co-flowing water. An experimental work was conducted in a loop in which pure water was circulated. The gas-injection nozzle was submerged in the flowing water. Effects of the water flow velocity and gas flow rate were jointly considered. Two-phase flow patterns were visualized using the high-speed photography and then
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Dynamics of concentrated suspensions in two-dimensional channel flow for non-Newtonian slurries Int. J. Multiphase Flow (IF 3.083) Pub Date : 2021-02-27 R.H. Hernández
The evolution of concentrated particle suspensions in a two dimensional channel flow between parallel plates is considered. We developed a numerical model based on the finite volume method to solve the full unsteady Navier Stokes equations coupled to a constitutive advection-diffusion equation in order to determine shear-induced migration phenomenon in concentrated suspensions of monodisperse and non-colloidal
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Numerical investigations of Rayleigh–Taylor instability with a density gradient layer Comput. Fluids (IF 2.399) Pub Date : 2021-02-09 Yang Song; Pei Wang; Lili Wang
The Rayleigh-Taylor instability (RTI) with a density gradient layer was investigated by implicit large eddy simulations (ILES) in a framework of three dimensional compressible multiphase flow with the single fluid approximation. The simulations are firstly initialized by multi-mode random perturbations in classic RTI and the associated case with a premixed layer. It is found that the late time behaviours
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Impact of wall modeling on kinetic energy stability for the compressible Navier-Stokes equations Comput. Fluids (IF 2.399) Pub Date : 2021-02-17 Vikram Singh; Steven Frankel; Jan Nordström
Affordable, high order simulations of turbulent flows on unstructured grids for very high Reynolds’ number flows require wall models for efficiency. However, different wall models have different accuracy and stability properties. Here, we develop a kinetic energy stability estimate to investigate stability of wall model boundary conditions. Using this norm, two wall models are studied, a popular equilibrium
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Diffuse bounce back condition for lattice Boltzmann method Comput. Fluids (IF 2.399) Pub Date : 2021-02-23 Geng Liu; Taehun Lee
The lattice Boltzmann method has been widely used in curved and moving boundary fluid simulations. Both explicit and implicit treatments are studied to recover proper boundary conditions on Cartesian grids. These methods can describe curved boundaries more accurately and more smoothly than the staircase approximation. However, to improve the order of accuracy and to reduce the fluctuation of force
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