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Journal articles on the topic 'Carreau-Yasuda Model'

Author: Grafiati

Published: 4 June 2021

Last updated: 20 June 2025

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Hayat, Tasawar, Fahad M. Abbasi, Ahmed Alsaedi, and Fuad Alsaadi. "Hall and Ohmic Heating Effects on the Peristaltic Transport of a Carreau–Yasuda Fluid in an Asymmetric Channel." Zeitschrift für Naturforschung A 69, no. 1-2 (2014): 43–51. http://dx.doi.org/10.5560/zna.2013-0074.

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The effects of Hall current and Ohmic heating are analyzed for the peristaltic flow of a Carreau- Yasuda fluid in an asymmetric channel. The mathematical model for peristalsis of the Carreau- Yasuda fluid is provided for the first time in the literature. The problem is developed in the presence of viscous dissipation. Solutions for pressure gradient, stream function, axial velocity, and temperature are established and discussed. The heat transfer rate at the wall is first computed numerically and then examined. A comparative study for viscous, Carreau, and Carreau-Yasuda fluids is also made.

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Mo, Qi Mian, Shi Xun Zhang, Teng Fei Chen, and Wei Cao. "Fit and Evaluate the Viscous Models Used for ABS." Key Engineering Materials 905 (January 4, 2022): 231–37. http://dx.doi.org/10.4028/www.scientific.net/kem.905.231.

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Viscous models such as Bird-Carreau, Cross, modified Cross, Carreau-Yasuda and Power are often used in commercial software. In order to get the most suitable model, a series of rheological tests were carried out in this study, and a model fitting method based on least square approach was proposed. Combined with the WLF equation related to temperature, these five viscous models were fitted by the fitting method proposed in this paper. The calculated results of the fitted models are compared with the experimental data. The results show that, of the investigated five models, the Carreau-Yasuda and Cross type models can better describe the rheological characteristics of ABS, the Bird-Carreau model is the second, and the Power model is the poorest one. The fitted models are in good agreement with that by Polymat. Some models such as Cross and Power models fitted by the proposed method are even better than that by Polymat.

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Coclite, Alessandro, Giuseppe Coclite, and Domenico De Tommasi. "Capsules Rheology in Carreau–Yasuda Fluids." Nanomaterials 10, no. 11 (2020): 2190. http://dx.doi.org/10.3390/nano10112190.

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In this paper, a Multi Relaxation Time Lattice Boltzmann scheme is used to describe the evolution of a non-Newtonian fluid. Such method is coupled with an Immersed-Boundary technique for the transport of arbitrarily shaped objects navigating the flow. The no-slip boundary conditions on immersed bodies are imposed through a convenient forcing term accounting for the hydrodynamic force generated by the presence of immersed geometries added to momentum equation. Moreover, such forcing term accounts also for the force induced by the shear-dependent viscosity model characterizing the non-Newtonian behavior of the considered fluid. Firstly, the present model is validated against well-known benchmarks, namely the parabolic velocity profile obtained for the flow within two infinite laminae for five values of the viscosity model exponent, n = 0.25, 0.50, 0.75, 1.0, and 1.5. Then, the flow within a squared lid-driven cavity for Re = 1000 and 5000 (being Re the Reynolds number) is computed as a function of n for a shear-thinning (n < 1) fluid. Indeed, the local decrements in the viscosity field achieved in high-shear zones implies the increment in the local Reynolds number, thus moving the position of near-walls minima towards lateral walls. Moreover, the revolution under shear of neutrally buoyant plain elliptical capsules with different Aspect Ratio (AR = 2 and 3) is analyzed for shear-thinning (n < 1), Newtonian (n = 1), and shear-thickening (n > 1) surrounding fluids. Interestingly, the power law by Huang et al. describing the revolution period of such capsules as a function of the Reynolds number and the existence of a critical value, Rec, after which the tumbling is inhibited in confirmed also for non-Newtonian fluids. Analogously, the equilibrium lateral position yeq of such neutrally buoyant capsules when transported in a plane-Couette flow is studied detailing the variation of yeq as a function of the Reynolds number as well as of the exponent n.

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Robledo Blasco, L. E., B. A. Weiss, M. E. Berli, and J. Di Paolo. "NUMERICAL ANALYSIS OF VISCOELASTOHYDRODYNAMIC LUBRICATION IN KNEE PROSTHESIS WITH NON-NEWTONIAN FLUID." Anales AFA 33, Special Fluids (2022): 57–61. http://dx.doi.org/10.31527/analesafa.2022.fluidos.57.

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In this work, a computational model of thin film lubrication applied to a knee prosthesis was designed in order to make a comparison between three constitutive models, i.e. a power law, the Carreau-Yasuda model and the Cross model. The equivalent model of the knee prosthesis was modeled as a rigid cylinder on a deformable plane. The mechanical behavior of the deformable component representing the tibial base was assumed as a viscoelastic Standard Linear Solid(SLS). The governing equations were solved simultaneously with the determination of a free-moving boundary by implementing it in COMSOL Multiphysics software. The results obtained showed that the Cross model presents the highest shear rate value, the lowest film thickness and the dynamic viscosity with less variation along the lubrication channel, reaching a minimum viscosity value of 0.02 Pa.s. The Carreau-Yasuda model presents the highest value of friction coefficient, being 21.5 % higher than for the Power Law model and 3.67 % higher than the Cross model.

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Erwin and Jonathan Liviera Marpaung. "Modeling Arterial Blood Flow under Stenosis: A Comparative Study of Newtonian and Carreau-Yasuda Non-Newtonian Approaches." Journal of Research in Mathematics Trends and Technology 6, no. 2 (2024): 88–98. http://dx.doi.org/10.32734/jormtt.v6i2.18754.

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This study investigates the simulation of blood flow within arteries experiencing stenosis using both Newtonian and non-Newtonian models. The Newtonian model employs standard fluid dynamics assumptions, while the non-Newtonian Carreau-Yasuda model accounts for the unique viscoelastic properties of blood, providing a more accurate representation of its flow behavior under various shear rates. By utilizing COMSOL Multiphysics, the simulations are conducted with parameters including blood velocity, viscosity, and pressure in normal and narrowed artery conditions. Results reveal that while the Newtonian model predicts general flow patterns, it lacks the precision needed to reflect the complexities of blood behavior in stenosed regions. Conversely, the Carreau-Yasuda model demonstrates enhanced accuracy by capturing viscosity variations and pressure differentials, particularly in the narrowed artery sections, showing the significance of non-Newtonian characteristics in modeling blood flow. These findings underscore the potential of non-Newtonian models in improving diagnostic and therapeutic approaches for vascular conditions.

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Al-Ma’aiteh, Tareq I., and Oliver Krammer. "Non-Newtonian numerical modelling of solder paste viscosity measurement." Soldering & Surface Mount Technology 31, no. 3 (2019): 176–80. http://dx.doi.org/10.1108/ssmt-11-2018-0044.

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PurposeThe purpose of this paper is to present the establishment of a computational fluid dynamics model for investigating different non-Newtonian rheological models of solder pastes by simulating solder paste viscosity measurement. A combined material model was established which can follow the measured, apparent viscosity values with lower error.Design/methodology/approachThe model included a parallel plate arrangement of rheometers. The diameter of the plate was 50 mm, whereas the gap between the plates was 0.5 mm. Only one quarter of the plate was modelled to enable using fine enough mesh, while keeping the calculation time low. Non-Newtonian properties were set using user defined function in Ansys, based on the Cross and Carreau–Yasuda material models. The viscosity values predicted by the mathematical models were compared to measured viscosity values of different types of solder pastes.FindingsIt was found that the Cross model predicts the apparent viscosity with a relatively high error (even approximately 50 per cent) at lower shear rates, whereas the Carerau–Yasuda model has higher errors at higher shear rates. The application of the proposed, combined model can result in a much lower error in the apparent viscosity between the calculated and measured viscosity values.Originality/valueThe error of Cross and Carreau–Yasuda material models has not been investigated yet in details. The proposed, combined material model can be applied for subsequent simulations via the described UDF, e.g. in the numerical modelling of the stencil printing. This can result in a more accurate modelling of the stencil printing process, which is inevitable considering the printing of solder paste for today fine-pitch, small size components.

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Sara Bensilakhal, Redha Rebhi, Noureddine Hadidi, et al. "Bi-stability Bifurcation in Convection Double Diffusion Through a Shallow Horizontal Layer Saturated with a Complex Fluid." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 101, no. 1 (2023): 137–59. http://dx.doi.org/10.37934/arfmts.101.1.137159.

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The onset of non-linear convection in a porous layer saturated by a shear-thinning liquid is studied. The Carreau-Yasuda model is utilized for modeling the behavior of the working medium. Constant fluxes of heat and mass are defined on the horizontal surfaces of the cavity, while the vertical sides are assumed adiabatic. The parallel flow approximation and the finite difference approach are used to conduct the investigation analytically and numerically, respectively. The linear stability inspection of the convective and diffusive circumstances is carried out by taking into account an infinitesimal perturbation. The theory of linear stability is employed to determine the critical Rayleigh number for the motion from the rest state, Hopf bifurcation, and the transition from the stationary to oscillatory convection. Overall, the Carreau-Yasuda rheological parameters have a significant impact on the thresholds of convection. The most interesting findings of this study is highlighting the existence of a bi-stability phenomenon, i.e., the existence of two steady-state solutions, which was not observed before in non-Newtonian fluids convection.

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Gallegos-Infante, José Alberto, María del Pilar Galindo-Galindo, Martha Rocío Moreno-Jiménez, Nuria Elizabeth Rocha-Guzmán, and Rubén Francisco González-Laredo. "Effect of Aqueous Extracts of Quercus resinosa on the Mechanical Behavior of Bigels." Scientia Pharmaceutica 90, no. 4 (2022): 73. http://dx.doi.org/10.3390/scipharm90040073.

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Quercus resinosa leaves are rich in polyphenol compounds, however, they are unstable to several chemical and physical factors that limit their activity. Several methods have been developed to solve such problems, among which bigels can be mentioned and obtained using hydrogels and oleogels. The mechanical characterization of this type of materials is by using rheological methods. Although the use of these methods is well documented, the Carreau-Yasuda model has been little used to evaluate the effect of polyphenols on the mechanical behavior of bigels. Therefore, bigels were obtained from hydrogels (guar gum/xanthan gum, 0.5/0.5% w/v) and oleogels (sesame oil/sorbitan monostearate 10% w/w). Micrographs, linear viscoelasticity range, frequency sweep, and single shear tests were performed. The data were analyzed using ANOVA and Tukey test (p < 0.05); micrographs showed linear relationship between polyphenols concentration and droplet size. Liquid fraction of bigels showed a pseudoplastic behavior, while the parameters of Carreau-Yasuda model showed that the highest value of the complex viscosity at zero shear was at the lowest concentration of extract; the relaxation time presented the lowest value at higher concentrations of extracts. These results indicate that the presence of polyphenols modifyes the mechanical behavior of bigels.

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Amangeldi, Medeu, Yanwei Wang, Asma Perveen, Dichuan Zhang, and Dongming Wei. "An Iterative Approach for the Parameter Estimation of Shear-Rate and Temperature-Dependent Rheological Models for Polymeric Liquids." Polymers 13, no. 23 (2021): 4185. http://dx.doi.org/10.3390/polym13234185.

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Numerical flow simulations play an important role in polymer processing. One of the essential prerequisites for accurate and precise flow simulations is to obtain accurate materials functions. In the framework of the generalized Newtonian fluid model, one needs to obtain shear viscosity as a function of the rate-of-shear and temperature—as determined by rheometry—and then fitted to a mathematical model. Often, many subjectively perform the fitting without paying attention to the relative quality of the estimated parameters. This paper proposes a unique iterative algorithm for fitting the rate-of-shear and temperature-dependent viscosity model under the time–temperature superposition (TTS) principle. Proof-of-concept demonstrations are shown using the five-parameter Carreau–Yasuda model and experimental data from small-amplitude oscillatory shear (SAOS) measurements. It is shown that the newly proposed iterative algorithm leads to a more accurate representation of the experimental data compared to the traditional approach. We compare their performance in studies of the steady isothermal flow of a Carreau–Yasuda model fluid in a straight, circular tube. The two sets of parameters, one from the traditional approach and the other from the newly proposed iterative approach, show considerable differences in flow simulation. The percentage difference between the two predictions can be as large as 10% or more. Furthermore, even in cases where prior knowledge of the TTS shifting factors is not available, the newly proposed iterative approach can still yield a good fit to the experimental data, resulting in both the shifting factors and parameters for the non-Newtonian fluid model.

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Gijsen, F. J. H., F. N. van de Vosse, and J. D. Janssen. "Wall shear stress in backward‐facing step flow of a red blood cell suspension." Biorheology: The Official Journal of the International Society of Biorheology 35, no. 4-5 (1998): 263–79. http://dx.doi.org/10.1177/0006355x1998035004005008.

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An experimental investigation of the wall shear stress distribution downstream of a backward‐facing step is carried out. Flow in this geometry is considered to be representative of flow in large and medium sized curved arteries and bifurcations. The wall shear stress distribution was determined by measuring the deformation of a gel layer, attached to the wall downstream of the step. Speckle pattern interferometry was applied to measure the deformation of the gel layer. The measured deformation, combined with the properties of the gel layer, served as an input for a finite element solid mechanics computation to determine the stress distribution in the gel layer. The wall shear stress, required to generate the measured deformation of the gel layer, was determined from these computations. A Newtonian buffer solution and a non‐Newtonian red blood cell suspension were used as measuring fluids. The deformation of the gel layer was determined for a Newtonian buffer solution to evaluate the method and to obtain the properties of the gel layer. Subsequently, the wall shear stress distribution for the non‐Newtonian red blood cell suspension was determined for three different flow rates. The inelastic non‐Newtonian Carreau–Yasuda model served as constitutive model for the red blood cell suspension. Using this model, the velocity and wall shear stress distribution were computed by means of a finite element fluid mechanics computation. From the comparison between the numerical and the experimental results, it can be concluded that wall shear stresses, induced by the red blood cell suspension, can be modeled accurately by employing a Carreau–Yasuda model.

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Amina Ould Larbi, Redha Rebhi, Soufiane Rahal, et al. "Impact of Non-Newtonian Fluids' Rheological Behavior on Double- Diffusive Natural Convection in an Inclined Square Porous Layer." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 99, no. 2 (2022): 17–47. http://dx.doi.org/10.37934/arfmts.99.2.1747.

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In the current study, natural convection is numerically simulated in a shallow, porous, square cavity that is filled with a non-Newtonian fluid. In terms of temperature and concentration gradients (heat and mass fluxes), the active wall was seen as uniform and constant, whereas the other walls are adiabatic and impermeable. To analyze the behavior of shear-thinning fluids, a Carreau-Yasuda model is utilized, which is suitable for many non-Newtonian fluids. It is presummated that the fluid will fulfill the Boussinesq approximation, be laminar, and be incompressible.

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SÁNCHEZ, JORGE H., GERMÁN C. QUINTANA, and MERY E. FAJARDO. "Rheology of pulp suspensions of bleached sugarcane bagasse: Effect of consistency and temperature." TAPPI Journal 14, no. 9 (2015): 601–6. http://dx.doi.org/10.32964/tj14.9.601.

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Rheological properties, such as yield stress and apparent viscosity, of pulp suspensions of bleached sugarcane bagasse were studied in a stress-shear rate controlled rheometer using concentric cylinders geometry. Results were statistically analyzed and presented as a function of the suspension consistency (0.5% ≤ Cm ≤ 4.0%) and temperature (20°C, 40°C, and 60°C). The yield stress was influenced by the consistency and temperature. The apparent viscosity was influenced only by the consistency. A power law model was fitted to the experimental results of yield stress. In flow tests, all the suspensions showed shear-thinning behavior, which was in agreement with the Carreau-Yasuda model.

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Lee, Hsueh-Chen. "A nonlinear weighted least-squares finite element method for the Carreau–Yasuda non-Newtonian model." Journal of Mathematical Analysis and Applications 432, no. 2 (2015): 844–61. http://dx.doi.org/10.1016/j.jmaa.2015.07.012.

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Brandão, P. V., M. N. Ouarzazi, S. C. Hirata, and A. Barletta. "Darcy–Carreau–Yasuda rheological model and onset of inelastic non-Newtonian mixed convection in porous media." Physics of Fluids 33, no. 4 (2021): 044111. http://dx.doi.org/10.1063/5.0048143.

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Kayani, Sana Maryam, S. Hina, and M. Mustafa. "A New Model and Analysis for Peristalsis of Carreau–Yasuda (CY) Nanofluid Subject to Wall Properties." Arabian Journal for Science and Engineering 45, no. 7 (2020): 5179–90. http://dx.doi.org/10.1007/s13369-020-04359-z.

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el Gibaly, Ahmed, Omar A. El-Bassiouny, Omar Diaa, Ali I. Shehata, Tamer Hassan, and Khalid M. Saqr. "Effects of Non-Newtonian Viscosity on the Hemodynamics of Cerebral Aneurysms." Applied Mechanics and Materials 819 (January 2016): 366–70. http://dx.doi.org/10.4028/www.scientific.net/amm.819.366.

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The purpose of this study is to present a comparative study between Newtonian and non-Newtonian blood viscosity models for simulating the hemodynamic wall shear stress (WSS) of cerebral aneurysms. The non-Newtonian blood viscosity was modeled using the Carreau-Yasuda nonlinear model. Two realistic cerebral aneurysm models, derived from 3D angiography imaging, were studied and simulated via computational fluid dynamics solver based on finite volume method, with a pulsating sinusoidal waveform boundary conditions. The maximum wall shear stresses were found at the aneurysm’s neck and apex, the inlet arteriole recorded an average wall shear stress and as for the blebs and tips the wall shear stress values were remarkably low. The comparison indicated that non-Newtonian blood viscosity model predicted a lower range of WSS than of the Newtonian model, which provides more accuracy for simulating aneurysm hemodynamics.

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Almusallam, Abdulwahab S., Isameldeen E. Daffallah, and Lazhar Benyahia. "Modeling the Deformation of Shear Thinning Droplets Suspended in a Newtonian Fluid." Applied Rheology 30, no. 1 (2020): 151–65. http://dx.doi.org/10.1515/arh-2020-0113.

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Abstract In this work, we carried out numerical modeling of the large deformation of a shear thinning droplet suspended in a Newtonian matrix using the constrained volume model. The adopted approach was to consider making incremental corrections to the evolution of the droplet anisotropy equation in order to capture the experimental behavior of a shear thinning droplet when subjected to deformation due to imposed flow. The constrained volume model was modified by using different models to describe the viscosity of droplet phase: the Bautista et al. model, the Carreau-Yasuda model and the Power-law model. We found that by combining the constrained volume model with a simple shear thinning viscosity model we were able to describe the available experimental data for large deformation of a shear thinning droplet suspended in a Newtonian matrix. Moreover, we developed an equation approximating flow strength during droplet retraction, and we found that the model can accurately describe the experimental data of the retraction of a shear thinning droplet.

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Chuchalerm, Nattawan, Wannika Sawangtong, Benchawan Wiwatanapataphee, and Thanongchai Siriapisith. "Study of Non-Newtonian blood flow - heat transfer characteristics in the human coronary system with an external magnetic field." Mathematical Biosciences and Engineering 19, no. 9 (2022): 9550–70. http://dx.doi.org/10.3934/mbe.2022444.

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<abstract><p>This paper proposes a novel mathematical model of non-Newtonian blood flow and heat transfer in the human coronary system with an external magnetic field. As the blood viscosity is assumed to depend not only on shear rate but also on temperature and magnet strength, the modified Carreau-Yasuda viscosity model is formulated. The computational domain includes the base of the aorta, the right coronary artery, and the left coronary artery, with the left circumflex and left anterior descending arteries. The element-based finite volume method is derived for the solution of the proposed model. Numerical simulations are carried out to investigate the magnetic field effect on the blood flow-heat transfer characteristic in the human coronary system. It is found that the magnetic field has a significant impact on fluid viscosity, leading to enhanced fluid velocity.</p></abstract>

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Nisar, Zahid, and Humaira Yasmin. "Analysis of Motile Gyrotactic Micro-Organisms for the Bioconvection Peristaltic Flow of Carreau–Yasuda Bionanomaterials." Coatings 13, no. 2 (2023): 314. http://dx.doi.org/10.3390/coatings13020314.

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Nanofluids are considered as an effective way to enhance the thermal conductivity of heat transfer fluids. Additionally, the involvement of micro-organisms makes the liquid more stable, which is important in nanotechnology, bio-nano cooling systems, and bio-microsystems. Therefore, the current investigation focused on the examination of the thermodynamic and mass transfer of a Carreau–Yasuda magnetic bionanomaterial with gyrotactic micro-organisms, which is facilitated by radiative peristaltic transport. A compliant/elastic symmetric channel subject to partial slip constraints was chosen. The features of viscous dissipation and ohmic heating were incorporated into thermal transport. We use the Brownian and thermophoretic movement characteristics of the Buongiorno nanofluid model in this study. A set of nonlinear ordinary differential equations are created from the partial differential equations that control fluid flow. The governing system of differential equations is solved numerically via the shooting technique. The results of pertinent parameters are examined through velocity, temperature, motile micro-organisms, concentration, and heat transfer rate.

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Kumar, Nitesh. "Numerical Investigation on the effect of Blood pressure on Wall Shear Stress and Vorticity." WSEAS TRANSACTIONS ON BIOLOGY AND BIOMEDICINE 18 (April 15, 2021): 63–65. http://dx.doi.org/10.37394/23208.2021.18.7.

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Pulsatile blood flow through the human carotid artery is studied using Computational Fluid Dynamics (CFD) to investigate the effect of blood rheology on the hemodynamic parameters. The carotid artery model used is segmented and reconstructed from the Magnetic Resonance Images (MRI) of a specific patient. The results of a non-Newtonian (Carreau-Yasuda) model and a Newtonian model are studied and compared. The results are represented for each peak systole where it is observed that there is significant variation in the spatial parameters between the two models considered in the study. Comparison of local shear stress magnitude in different branches namely Common Carotid Artery (CCA), Internal Carotid Artery (ICA) and External Carotid Artery (ECA) show that the shear thinning property of blood influences the Wall Shear Stress (WSS) variation. This is observed in branches where there is reduction in diameter and where the diameter reduces due to plaque deposition and also in the region where there is flow recirculation like carotid sinus

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Lu, Hong Xing, Xiao Xia Meng, Nov Bunnareaksathya, and Qiang Zhu. "Rheological Modeling of 7075 Aluminum Alloy Semi-Solid Slurry and its Application in the Simulation of SEED Rheocasting Process." Solid State Phenomena 347 (August 24, 2023): 165–69. http://dx.doi.org/10.4028/p-q03dx8.

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Rheocasting technology has been successfully applied to produce aluminum alloy parts of automobile and communication equipment. However, its application scope is still limited. One reason is that the strength of the applied alloys is limited. In recent years, lots of researchers have tried to use 7075 aluminum alloy in the rheocasting process because this alloy has excellent mechanical properties. In this work, the rheological behavior of 7075 aluminum alloy semi-solid slurry is studied through shear stress-controlled test and shear rate-controlled test. Then the constitutive parameters in Power-Law (PL) model or Carreau-Yasuda (CY) model of non-Newtonian fluid are determined. The models are used to simulate the flow behavior of 7075 aluminum alloy semi-solid slurry in Swirled Enthalpy Equilibration Device (SEED) rheocasting process. The simulation results indicate that the CY model derived from the shear rate sweep test is more suitable for simulating the flow behavior of 7075 aluminum alloy semi-solid slurry during rheocasting than the other models.

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Zangooei, Hossein, Seyed Ali Mirbozorgi, and Seyedabdollah Mirbozorgi. "Dependence of Temperature Rise on the Position of Catheters and Implants Power Sources Due to the Heat Transfer into the Blood Flow." Electronics 11, no. 12 (2022): 1878. http://dx.doi.org/10.3390/electronics11121878.

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This work provides a numerical analysis of heat transfer from medical devices such as catheters and implants to the blood flow by considering the relative position of such power sources to the vessel wall. We have used COMSOL Multiphysics® software to simulate the heat transfer in the blood flow, using the finite element method and Carreau-–Yasuda fluid model (a non-Newtonian model for blood flow). The location of the power source is changed (from the center to near the wall) in the blood vessel with small steps, while the blood flow takes different velocities. The numerical simulations show that when the catheter/implant approaches the vessel wall, the temperature increases linearly for ~90% of the radial displacement from the centerline position to the vessel wall, while for the last 10% of the radial displacement, the temperature increases exponentially. As a result, the temperature is increased significantly, when changing the position of the catheter/implant from the centerline to the area adjacent to the vessel wall.

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Bakak, Abderrahim, Mohamed Lotfi, Rodolphe Heyd, Amine Ammar, and Abdelaziz Koumina. "Viscosity and Rheological Properties of Graphene Nanopowders Nanofluids." Entropy 23, no. 8 (2021): 979. http://dx.doi.org/10.3390/e23080979.

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The dynamic viscosity and rheological properties of two different non-aqueous graphene nano-plates-based nanofluids are experimentally investigated in this paper, focusing on the effects of solid volume fraction and shear rate. For each nanofluid, four solid volume fractions have been considered ranging from 0.1% to 1%. The rheological characterization of the suspensions was performed at 20 ∘C, with shear rates ranging from 10−1s−1 to 103s−1, using a cone-plate rheometer. The Carreau–Yasuda model has been successfully applied to fit most of the rheological measurements. Although it is very common to observe an increase of the viscosity with the solid volume fraction, we still found here that the addition of nanoparticles produces lubrication effects in some cases. Such a result could be very helpful in the domain of heat extraction applications. The dependence of dynamic viscosity with graphene volume fraction was analyzed using the model of Vallejo et al.

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Genoyer, Julie, Emna Helal, Giovanna Gutierrez, Nima Moghimian, Eric David, and Nicole R. Demarquette. "Graphene and Nanoclay as Processing Aid Agents: A Study on Rheological Behavior in Polystyrene." C 9, no. 4 (2023): 96. http://dx.doi.org/10.3390/c9040096.

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The effectiveness of layered particles as processing aid agents in molten polystyrene was studied. Three graphene grades and two clays of different lateral size were selected for this purpose. The morphologies of the composites were observed using scanning electron microscopy. Steady shear measurements were carried out and the Carreau–Yasuda model with yield stress was applied to the experimental results. A decrease in viscosity was observed at 2 wt.% of particle content for almost all composites. The most efficient particle for reducing viscosity was found to be graphene in a loose agglomerated configuration. Graphene and clay particles with similar dispersion states had a similar effect on the viscosity, inducing a decrease by 29% and 22%, respectively, suggesting comparable efficiency as processing aid agents. The observed decrease in viscosity is attributed to the phenomenon of superlubricity, which is a lubricating mechanism that is closely linked to the atomic structure of the particles.

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Umar, Farida Mustapha, and M. H. Ali. "Evaluation of the effect of viscosity on blood flow using viscosity models." Dutse Journal of Pure and Applied Sciences 10, no. 3c (2024): 230–34. http://dx.doi.org/10.4314/dujopas.v10i3c.22.

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The study of blood hemodynamics and rheological properties, particularly blood viscosity, is essential for understanding and treating certain cardiovascular conditions. Blood is a non-Newtonian fluid, meaning its viscosity varies with shear rate, a behavior driven by the aggregation and deformation of red blood cells (RBCs). Accurate modeling of blood viscosity is therefore critical for simulating blood flow in both physiological and pathological states. In this work, various viscosity models were assessed to identify the most suitable that represents the blood’s behavior in relation to shear rate. Although the Newtonian model is simple, it fails to capture the non-Newtonian characteristics of blood, particularly at varying shear rates. In comparison, the Power Law, Walburn-Schneck, and Carreau-Yasuda models offer more detailed and complex approaches to modeling blood viscosity. The Effect of blood viscosity on the overall blood flow was evaluated based on the four viscosity models. The work was carried out in a MATLAB Simulation Environment. The Volumetric blood flow rate was evaluated from the Poiseuille’s equation using three viscosity models whose values were defined by shear rates ranging from (217.5 – 226.5)s−1 . The percentage change in the blood volume resulting from changes in the viscosity was examined for each model. The two viscosity models (Power and Carreau models) concurrently reported equal percentage change of blood flux variation with the corresponding variation of the viscosity due to change in shear rate. This shows that any of the two models can be used to study the variation of blood flow to the viscosity with respect to cardiovascular complications.

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Samad, Abdus, A. Husain, M. Zunaid, and A. Samad. "Newtonian and Non-Newtonian Pulsatile Flows through an Artery with Stenosis." Journal of Engineering Research [TJER] 14, no. 2 (2017): 191. http://dx.doi.org/10.24200/tjer.vol14iss2pp191-205.

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The current study presents three-dimensional modeling and analysis of blood flow through artery stenosis under several variants of pulsatile flow to mimic the atherosclerosis artery disease. The study considered Newtonian and non-Newtonian blood flow models and solved the three-dimensional laminar and unsteady Navier-Stokes (NS) equations for different inlet velocity profiles. The Carreau Yasuda model was used for hemodynamics modeling of fluid viscosity. A comparative analysis was carried out for Newtonian and non-Newtonian fluid models under several simple pulsatile, equivalent pulsatile and physiological velocity profiles. The non-Newtonian fluid exhibited a higher centerline velocity. Wall shear stresses, shear strain rates, velocity fields, and vortex distribution for Newtonian and non-Newtonian fluid flows show significant differences. A higher wall shear was noticed near the stenosis. The vortex formed near the stenosis shifts to upstream and downstream of the stenosis with the change of velocity pulse. The velocity profile deflates more for non-Newtonian flows than the Newtonian flows.

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Hussain, Azad, Aysha Rehman, Sohail Nadeem, et al. "A Combined Convection Carreau–Yasuda Nanofluid Model over a Convective Heated Surface near a Stagnation Point: A Numerical Study." Mathematical Problems in Engineering 2021 (April 3, 2021): 1–14. http://dx.doi.org/10.1155/2021/6665743.

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The focus of this manuscript is on two-dimensional mixed convection non-Newtonian nanofluid flow near stagnation point over a stretched surface with convectively heated boundary conditions. The modeled equation representing nonlinear flow is transformed into a system of ordinary differential equations by implementing appropriate similarity transformations. The generated structure is numerically solved by applying the bvp4c method. Consequences of various involved parameters, e.g., stretching parameter, mixed convection parameter, thermophoresis parameter, Brownian movement parameter, Lewis number, Weissenberg number, Prandtl number, Biot number, buoyancy ratio parameter, mass and heat transport rates on temperature and velocity, the stretched surface, and nanoparticle concentration patterns are analyzed. Outcomes are shown graphically and displayed in tables. Velocity fluctuations are responded to by growing parameters of mixed convection and Weissenberg number. Concentration and thermal fields are also discovered for the Prandtl number. There are also flow line diagrams to analyze the behavior.

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Bernabeu, Miguel O., Rupert W. Nash, Derek Groen, et al. "Impact of blood rheology on wall shear stress in a model of the middle cerebral artery." Interface Focus 3, no. 2 (2013): 20120094. http://dx.doi.org/10.1098/rsfs.2012.0094.

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Perturbations to the homeostatic distribution of mechanical forces exerted by blood on the endothelial layer have been correlated with vascular pathologies, including intracranial aneurysms and atherosclerosis. Recent computational work suggests that, in order to correctly characterize such forces, the shear-thinning properties of blood must be taken into account. To the best of our knowledge, these findings have never been compared against experimentally observed pathological thresholds. In this work, we apply the three-band diagram (TBD) analysis due to Gizzi et al. (Gizzi et al. 2011 Three-band decomposition analysis of wall shear stress in pulsatile flows. Phys. Rev. E 83 , 031902. ( doi:10.1103/PhysRevE.83.031902 )) to assess the impact of the choice of blood rheology model on a computational model of the right middle cerebral artery. Our results show that, in the model under study, the differences between the wall shear stress predicted by a Newtonian model and the well-known Carreau–Yasuda generalized Newtonian model are only significant if the vascular pathology under study is associated with a pathological threshold in the range 0.94–1.56 Pa, where the results of the TBD analysis of the rheology models considered differs. Otherwise, we observe no significant differences.

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Cao, Qin-Liu, Mehrdad Massoudi, Wen-He Liao, Feng Feng, and Wei-Tao Wu. "Flow Characteristics of Water-HPC Gel in Converging Tubes and Tapered Injectors." Energies 12, no. 9 (2019): 1643. http://dx.doi.org/10.3390/en12091643.

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Gelled fuels combine the main advantages of liquid fuels (throttle ability) and solid fuels (easy handling, etc.) due to their non-Newtonian characteristics. In this paper, we study the flow characteristics of water-hydroxypropylcellulose (HPC) gel in converging tubes and tapered injectors which mimic the flow and injection of kerosene gel in typical geometries of propulsion systems. The water-HPC gel is modeled as a non-linear fluid, where the shear viscosity is assumed to depend on the local shear rate and modeled by the Carreau–Yasuda model; the model parameters are fitted with our experimental measurements done by a rotational rheometer. The numerical simulations indicate that for the converging tubes, increasing the convergence angle, causes the mean apparent viscosity at tube exit to decrease while the mass flow rate reduces at a constant pressure drop. Therefore, there is a balance between the lowering of the pressure loss and reducing mean apparent viscosity. In the tapered injectors, the straight pipe after the converging part has a detrimental effect on the viscosity reduction.

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Müser, Martin H. "Shear Thinning in the Prandtl Model and Its Relation to Generalized Newtonian Fluids." Lubricants 8, no. 4 (2020): 38. http://dx.doi.org/10.3390/lubricants8040038.

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The Prandtl model is certainly the simplest and most generic microscopic model describing solid friction. It consists of a single, thermalized atom attached to a spring, which is dragged past a sinusoidal potential representing the surface energy corrugation of a counterface. While it was primarily introduced to rationalize how Coulomb’s friction law can arise from small-scale instabilities, Prandtl argued that his model also describes the shear thinning of liquids. Given its success regarding the interpretation of atomic-force-microscopy experiments, surprisingly little attention has been paid to the question how the Prandtl model relates to fluid rheology. Analyzing its Langevin and Brownian dynamics, we show that the Prandtl model produces friction–velocity relationships, which, converted to a dependence of effective (excess) viscosity on shear rate η ( γ ˙ ) , is strikingly similar to the Carreau–Yasuda (CY) relation, which is obeyed by many non-Newtonian liquids. The two dimensionless parameters in the CY relation are found to span a broad range of values. When thermal energy is small compared to the corrugation of the sinusoidal potential, the leading-order γ ˙ 2 corrections to the equilibrium viscosity only matter in the initial part of the cross-over from Stokes friction to the regime, where η obeys approximately a sublinear power law of 1 / γ ˙ .

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Selma Lounis, Redha Rebhi, Noureddine Hadidi, et al. "Thermo-Solutal Convection of Carreau-Yasuda Non-Newtonian Fluids in Inclined Square Cavities Under Dufour and Soret Impacts." CFD Letters 14, no. 3 (2022): 96–118. http://dx.doi.org/10.37934/cfdl.14.3.96118.

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The thermosolutal convection of non-Newtonian fluids under Soret and Dufour influences within an inclined square enclosure is explored. The active walls are subject to constant and uniform concentrations and temperatures. On the other hand, they are impermeable and adiabatic. A Carreau-Yasuda model is utilized to determine the fluid behavior. A special attention is paid to the impact of rheological parameters (, , and ), the thermal Rayleigh number , Dufour number, , Soret number, , Lewis number, , buoyancy ratio, , and the inclination angel, . The numerical findings are represented in terms thermal fields, iso-concentration, and viscosity apparent contours, and the influence of certain parameters on the variation of stream function, Nusselt and Sherwood numbers, and apparent viscosity is also inspected. The findings suggest that the rise of the time constant parameter, , causes an increase in thermal and mass exchange for various power-law indices, . The decrease of the of ratio of infinite-to zero-shear-rate viscosities, , and parameter, , enhances the both thermal and mass transfers. The rise of the orientation angel from 0° to 90°yields an increase in thermal and mass transfer, but without a specific pattern in the different parameters studied.

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Ahmad, Bilal, Muhammad Ozair Ahmad, Liaqat Ali, et al. "Significance of the Coriolis Force on the Dynamics of Carreau–Yasuda Rotating Nanofluid Subject to Darcy–Forchheimer and Gyrotactic Microorganisms." Mathematics 10, no. 16 (2022): 2855. http://dx.doi.org/10.3390/math10162855.

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In this study, the significance of the Coriolis force on the dynamics of Carreau—Yasuda flow toward a continuously stretched surface subject to the Darcy–Forchheimer law is investigated. The nanoparticles are incorporated due to their unusual characteristics (e.g., extraordinary thermal conductivity), which are significant in heat exchangers and advanced nanotechnology. To avoid possible sedimentation of tiny particles, the gyrotactic microorganisms must be incorporated. The goal of this research was to find out the dynamics of three-dimensional rotational flow for nanofluids under the influence of Darcy–Forchheimer with the thermophoresis effect and motile microorganisms. The equations governing mass, momentum, and energy equations are formalized using partial derivatives, which may subsequently be transformed into dimensionless differential shapes using the personifications of apposite similarity transformations. The MATLAB application bvp4c was used in conjunction with a shooting technique to solve a nonlinear mathematical model based on ordinary differential equations. It was observed that the base fluid velocities decreased against higher input of rotation and porosity parameters; moreover, the Brownian motion and thermophoresis increased the temperature profile.

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Park, In Hye, Jae Yoon Lee, Seung Jae Ahn, and Hyoung Jin Choi. "Melt Rheology and Mechanical Characteristics of Poly(Lactic Acid)/Alkylated Graphene Oxide Nanocomposites." Polymers 12, no. 10 (2020): 2402. http://dx.doi.org/10.3390/polym12102402.

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Poly(lactic acid) (PLA) nanocomposites were synthesized by a solution blending and coagulation method using alkylated graphene oxide (AGO) as a reinforcing agent. Turbiscan confirmed that the alkylation of GO led to enhanced compatibility between the matrix and the filler. The improved dispersity of the filler resulted in superior interfacial adhesion between the PLA chains and AGO basal plane, leading to enhanced mechanical and rheological properties compared to neat PLA. The tensile strength and elongation at break, i.e., ductility, increased by 38% and 42%, respectively, at the same filler content nanocomposite (PLA/AGO 1 wt %) compared to nonfiller PLA. Rheological analysis of the nanocomposites in the molten state of the samples was performed to understand the filler network formed inside the matrix. The storage modulus increased significantly from PLA/AGO 0.5 wt % (9.6 Pa) to PLA/AGO 1.0 wt % (908 Pa). This indicates a percolation threshold between the two filler contents. A steady shear test was performed to examine the melt flow characteristics of PLA/AGO nanocomposites at 170 °C, and the viscosity was predicted using the Carreau−Yasuda model.

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Chafidz, Achmad, Venitalitya Augustia, Ariany Zulkania, Asmanto Subagyo, Mujtahid Kaavessina, and Muhammad Rizal. "Date Palm Fiber Reinforced High Density Polyethylene Composites: Effect of Fiber Loadings on the Melt Rheological Behavior." Key Engineering Materials 773 (July 2018): 40–45. http://dx.doi.org/10.4028/www.scientific.net/kem.773.40.

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In the recent years, the trend of using renewable source (green) fillers in the composites fabrication is increasing. One of these green fillers is natural fibers, which referred to the plant fibers, such as date palm fiber (DPF). In the present work, high-density polyethylene (HDPE)/DPF composites have been prepared. Four different DPF loadings were used (i.e. 0, 5, 10, 20 wt%) to prepare the composites. The effect of DPF loadings on the melt rheological behavior of the HDPE/DPF composites were studied. The melt rheological test results showed that both of storage modulus (Gʹ) and loss modulus (Gʺ) increased with the increase of DPF loadings. Additionally, the Han plot showed an upward shift from neat HDPE (i.e. DFC-0) to DFC-20, which indicated that the melt rheological properties changed with the increase of DPF loadings. The complex viscosity |h*| of the composites samples also increased with the increase of DPF loadings. The increased was more significant at higher DPF loadings (i.e. DFC-20). Meanwhile, the Carreau-Yasuda model was found to be well fitted with the experimental data.

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Ali Benyahia, B., and N. Ait Messouadene. "Rayleigh-Benard convection study in a cavity for a shear thinning fluid." Journal of Fundamental and Applied Sciences 13, no. 3 (2021): 1361–79. http://dx.doi.org/10.4314/jfas.v13i3.14.

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 Rayleigh-Bénard's convection is a classic problem of heat transfer. Since the 1900s, studies for Newtonian fluids have been widely developed in this field and phenomena well understood. On the other hand, the complexity of non-Newtonian behavior makes the number of studies much lower. Among the non-Newtonian behavior, the shear-thinning fluid studies are even rarer. This work focuses on a numerical study of natural convection for a non-Newtonian fluid shear thinning, in the Rayleigh-Bénard configuration. The Carreau-Yasuda model describes the shear thinning behavior. The convective flow considered is confined in a cavity, which is subjected to a vertical temperature gradient, heated from below and cooled from above. The transport equations are discretized by the finite volume method and are solved numerically using a CFD code: "Ansys Fluent". The influence of the control parameters on the flow and heat transfer such as the Rayleigh 𝑅𝑎 number, the aspect ratio, 𝐴, the Prandtl numbers, 𝑃𝑟, the power index 𝑛 and the time constant 𝐸, are studied.

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Sharipkhan, Nurdaulet, Omonini Clifford, Asma Perveen, Di Chuan Zhang, and Dong Ming Wei. "Investigation of Co-Extrusion Using a Coat Hanger Die with Different Feedblock Cross-Section." Key Engineering Materials 973 (February 9, 2024): 131–37. http://dx.doi.org/10.4028/p-rctkv4.

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When using the coat hanger die method for co-extrusion, the biggest challenges often involve maintaining the uniformity of the velocity distribution at the outlet of the die and ensuring the stability of the interface plane. This paper investigates the effect of different cross-section of feed channels connected to the coat hanger die on the velocity and pressure distribution of the flow at different parts of the die. Co-extrusion of LLDPE (Linear Low Density Polyethylene) and HDPE (High Density Polyethylene) polymers is simulated using ANSYS software 2020 R2 for coat hanger die design with rectangular and circular cross-sections inlet geometry; the results are compared for Carreau-Yasuda model to observe the result differences between rectangular and circular coextrusion channels connected to coat hanger die. Our results showed that rectangular cross-section feedblock generated higher values for pressure in comparison with the pressure generated by the circular cross-section feedblock. The maximum velocity generated in the circular feedblock is lower than that generated in the rectangular one, nevertheless there is more uniformity in velocity distribution in circular than rectangular cross-section.

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Venczel, Márk, Gabriella Bognár, and Árpád Veress. "Temperature-Dependent Viscosity Model for Silicone Oil and Its Application in Viscous Dampers." Processes 9, no. 2 (2021): 331. http://dx.doi.org/10.3390/pr9020331.

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Silicone fluids belong to the group of pseudoplastic non-Newtonian fluids with complex rheological characteristics. They are considered in basic and applied researches and in a wide range of industrial applications due to their favorable physical and thermal properties. One of their specific field of applications in the automotive industry is the working fluid of viscous torsional vibration dampers. For numerical studies in the design and development phase of this damping product, it is essential to have thorough rheological knowledge and mathematical description about the silicone oil viscosity. In the present work, adopted rheological measurement results conducted on polydimethylsiloxane manufactured by Wacker Chemie with initial viscosity of 1000 Pas (AK 1 000 000 STAB silicone oil) are processed. As a result of the parameter identification by nonlinear regression, the temperature-dependent parameter curves of the Carreau–Yasuda non-Newtonian viscosity model are generated. By implementing these parameter sets into a Computational Fluid Dynamics (CFD) software, a temperature- and shear-rate-dependent viscosity model of silicone fluid was tested, using transient flow and thermal simulations on elementary tube geometries in the size range of a real viscous torsional vibration damper’s flow channels and filling chambers. The numerical results of the finite volume method provide information about the developed flow processes, with especial care for the resulted flow pattern, shear rate, viscosity and timing.

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Shukor, Mohd Yunus. "Outlier and Normality Testing of the Residuals from the Carreau-Yasuda Model in Fitting the Rheological Behavior of the Non-Newtonian fluid TF2N." Bioremediation Science and Technology Research 9, no. 1 (2021): 20–26. http://dx.doi.org/10.54987/bstr.v9i1.593.

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Non-Newtonian fluids include a variety of regularly encountered substances such as custard, honey, toothpaste, starch suspensions (including starch from corn starch), paint, blood, melted butter, and hairspray. For decades, scientists have investigated non-Newtonian fluid behavior and produced models to aid in the characterization of non-Newtonian fluid behavior. In addition to data interpolation and extrapolation, the outputs of these models may be utilized for material classification based on model parameters and aid with the simulation of computational fluid dynamics. The Carreau-Yasuda model fitted to the rheological behavior of the non-Newtonian fluid1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([emim][TF2N]) was checked for its conformation to the normal distribution of its residual using the normality tests , which was found not to pass all of the test. After checking for the presence of an outlier using the Grubbs â€˜test, no outlier was detected. The ROUT method was then applied to detect the presence of outliers and three outliers were found and removed. The normality checks performed on the cleaned residues gave acceptable results in terms of normality tests and visual conformation of the residual, Q-Q plot and overlaid normality curve to the histogram, indicating that the model is now appropriate for the data.

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Mustafaoğlu, Mansur, İsak Kotçioğlu, and Muhammet Kaan Yeşilyurt. "Numerical analysis of the three-dimensional model of pulsatile and non-Newtonian blood flow in a carotid artery with local occlusion." Mathematical Modelling and Numerical Simulation with Applications 5, no. 1 (2025): 97–116. https://doi.org/10.53391/mmnsa.1522021.

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The analysis of blood flow in blood vessels, particularly in arteries, is a topic with important clinical applications. The blood can undergo a reduction in its viscosity under shear stress, which is called shear thinning. In this study, the effect of the shear thinning of blood is simulated using the Carreau-Yasuda model, neglecting the viscoelastic effects. The purpose of this investigation is to analyze the pulsatile blood flow in a three-dimensional model of the carotid artery and the effects of occlusion using Ansys Fluent. The results obtained in this study show that, compared to Newtonian fluids, non-Newtonian fluids exhibit significant differences in secondary flow patterns and shear flow behavior. Additionally, the axial velocity in the non-planar branch decreases with obstruction. The maximum shear stress of the walls with Newtonian fluid viscosity exhibits a significant error, and the values are lower than those of walls with non-Newtonian viscosity in most cases. In continuation of this research, vessel occlusion models with different occlusion sizes are analyzed. In the case where the outlet of the vessel is narrowed, an increase in velocity is observed in the furcation area. Although the software cannot simulate rupture, occlusion of the vessel at 80\% and 50\% of the internal diameter is analyzed.

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David, J., P. Filip, and A. A. Kharlamov. "Empirical Modelling of Nonmonotonous Behaviour of Shear Viscosity." Advances in Materials Science and Engineering 2013 (2013): 1–4. http://dx.doi.org/10.1155/2013/658187.

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Almost all hitherto proposed empirical models used for characterization of shear viscosity of non-Newtonian liquids describe only its monotonous course. However, the onset of new materials is accompanied by more complicated characteristics of their behaviour including nonmonotonous course of shear viscosity. This feature is reflected not only in an existence of one extreme point (maximum or minimum), but also it can appear in both extreme points; that is, this shear viscosity initially exhibits shear thinning; after attaining a local minimum, it converts to shear thickening, and again after reaching a local maximum, it has a shear-thinning character. It is clear that, for an empirical description of this complex behaviour, a hitherto, used number of parameters (four, five) in classical monotonous models (such as Cross or Carreau-Yasuda) are no longer tenable. If more parameters are applied, there should be given an emphasis on a relatively simple algebraic form of the proposed models, unambiguity of the involved parameters, and their sound interpretation in the whole modelling. This contribution provides an overview of the existing empirical nonmonotonous models and proposes a new 10-parameter model including a demonstration of its flexibility using various experimental data.

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Ahmed, Istiaque, Hari Poudyal, and Abhilash J. Chandy. "TWO-DIMENSIONAL NONISOTHERMAL NUMERICAL ANALYSIS OF SPEED RATIO EFFECTS ON DISPERSION AND DISTRIBUTION IN HIGH-VISCOSITY PARTIALLY FILLED RUBBER MIXING." Rubber Chemistry and Technology 92, no. 1 (2019): 168–85. http://dx.doi.org/10.5254/rct.19.82583.

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ABSTRACT Two-dimensional, transient, and nonisothermal computational fluid dynamics simulations are conducted for high-viscosity rubber mixing in a two-wing rotor-equipped partially filled chamber of fill factor 75%. Calculations presented assess the effect of three differential speeds or speed ratios of the two rotors for the rubber mixing process: 1.0 (also called even speed), 1.125, and 1.5. A Eulerian multiphase model, the volume of fluid technique, is employed to simulate two different phases, rubber and air, by calculating the free surface between the two phases, in addition to the main governing equations such as the continuity, momentum, and energy equations. To characterize the non-Newtonian, highly viscous rubber under nonisothermal conditions, the shear rate–dependent Carreau-Yasuda model along with an Arrhenius function are employed. A set of massless particles is introduced into the chamber to calculate several parameters related to dispersive and distributive mixing characteristics. Specifically, the mixing index and maximum shear stress are analyzed for the dispersive nature, whereas cluster distribution index and length of stretch are calculated for investigating the distributive nature of the mixing process. Also, the temporal viscous heat generation rate, a good indication of the temperature rise throughout the domain, which is critical in the process and equipment design, is analyzed here. Results showed that the 1.125 speed ratio was the most efficient in terms of distributive mixing and heat generation.

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Dubey, Ankita, Vasu B., O. Anwar Bég, and R. S. R. Gorla. "Finite element computation of magneto-hemodynamic flow and heat transfer in a bifurcated artery with saccular aneurysm using the Carreau-Yasuda biorheological model." Microvascular Research 138 (November 2021): 104221. http://dx.doi.org/10.1016/j.mvr.2021.104221.

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Zare, Yasser, Sang Phil Park, and Kyong Yop Rhee. "Analysis of complex viscosity and shear thinning behavior in poly (lactic acid)/poly (ethylene oxide)/carbon nanotubes biosensor based on Carreau–Yasuda model." Results in Physics 13 (June 2019): 102245. http://dx.doi.org/10.1016/j.rinp.2019.102245.

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Santesarti, Gianluca, Michele Marino, Francesco Viola, Roberto Verzicco, and Giuseppe Vairo. "An insight into parameter identifiability issues in the Carreau–Yasuda model: A more consistent rheological formulation for shear-thinning non-Newtonian inelastic fluids." Journal of Non-Newtonian Fluid Mechanics 342 (August 2025): 105438. https://doi.org/10.1016/j.jnnfm.2025.105438.

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Lee, Kok Peng Marcian, Milan Brandt, Robert Shanks, and Fugen Daver. "Rheology and 3D Printability of Percolated Graphene–Polyamide-6 Composites." Polymers 12, no. 9 (2020): 2014. http://dx.doi.org/10.3390/polym12092014.

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Graphene–polyamide-6 (PA6) composites with up to 17.0%·w/w graphene content were prepared via melt mixing. Oscillatory rheometry revealed that the dynamic viscoelastic properties of PA6 decreased with the addition of 0.1%·w/w graphene but increased when the graphene content was increased to 6.0%·w/w and higher. Further analysis indicated that the rheological percolation threshold was between 6.0 and 10.0%·w/w graphene. The Carreau–Yasuda model was used to describe the complex viscosity of the materials. Capillary rheometry was applied to assess the steady shear rheology of neat PA6 and the 17.0%·w/w graphene–PA6 composite. High material viscosity at low shear rates coupled with intense shear-thinning in the composite highlighted the importance of selecting the appropriate rheological characterisation methods, shear rates and rheological models when assessing the 3D printability of percolated graphene–polymer composites for material extrusion (ME). A method to predict the printability of an ME filament feedstock, based on fundamental equations describing material flow through the printer nozzle, in the form of a printing envelope, was developed and verified experimentally. It was found that designing filaments with steady shear viscosities of approximately 15% of the maximum printable viscosity for the desired printing conditions will be advantageous for easy ME processing.

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Fernandes, Ignatius, and Nitin Bodke. "FORCED CONVECTION IN A LID-DRIVEN NON-NEWTONIAN BLOOD FLOW THROUGH A STENOTIC ARTERY." Journal of the Serbian Society for Computational Mechanics 15, no. 1 (2021): 65–80. http://dx.doi.org/10.24874/jsscm.2021.15.01.05.

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Cardiovascular diseases are one of the major health concerns globally, mainly caused by inadequate blood flow in different body parts. The lack of blood flow is often due to abnormal narrowing of blood vessels, and a systematic technique to boost blood flow in these areas can help cure the disease. One such method uses elevated temperatures to influence blood flow in the concerned areas. This paper investigates this process, i.e. the forced convection, through blood flow in a stenotic region of a human artery. A part of the stenotic region is considered a porous medium and the top wall is subjected to a higher temperature with a lid moving from left to right. Blood is considered as a non-Newtonian fluid with the power law index varying from 0.5 to 1.5. The geometric properties are considered to match the problem of blood flow in the artery affected by stenosis. The Carreau-Yasuda model is used to represent the non-Newtonian fluid flow in porous media and the numerical analysis is carried out using the Lattice Boltzmann method. This problem is investigated to study the influence of the moving lid and other geometric properties on convection and flow properties such as velocity profiles, streamlines, isotherms and heat transfer.

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Hodgkinson, Richard, Stephen T. Chaffin, William B. J. Zimmerman, Chris Holland, and Jonathan R. Howse. "Extensional flow affecting shear viscosity: Experimental evidence and comparison to models." Journal of Rheology 66, no. 4 (2022): 793–809. http://dx.doi.org/10.1122/8.0000380.

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The effect of extensional flow on apparent shear viscosity has never previously been directly measured nor is it often considered. Here, for the first time, through using a novel flow configuration (two-phase shear response under extensional flow), we have directly measured the effect extensional flow has on the apparent shear viscosity of a viscoelastic polymer solution in a controlled and kinematically mixed manner. We show, via a control transient shear experiment, that the apparent shear viscosity of the solution under mixed deformation depends not only on the shear rate but also on the extension rate and their relative direction: shear thinning being enhanced by parallel and reduced by perpendicular extensional flow, respectively. A 62% reduction in apparent viscosity with parallel extension was seen in this work. We then test the ability of the commonly used Giesekus and Carreau–Yasuda (incorporating generalized shear rate) models to predict the effect of extension rate on apparent shear viscosity against our data. The Giesekus model was found to predict the correct qualitative behavior under both parallel and perpendicular extensional flow, and depending on the fitting parameters, also provided a loosely quantitative agreement. Conversely, the generalized shear rate description does not capture the qualitative behavior, with the most significant errors occurring for perpendicular extension (i.e., expansion) flows. This work emphasizes the rarely noted shortcomings of the latter approach when used for experimental analysis and engineering design when extensional flows are additionally present.

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Razeghiyadaki, Amin, Dongming Wei, Asma Perveen, and Dichuan Zhang. "A Multi-Rheology Design Method of Sheeting Polymer Extrusion Dies Based on Flow Network and the Winter–Fritz Design Equation." Polymers 13, no. 12 (2021): 1924. http://dx.doi.org/10.3390/polym13121924.

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In the polymer sheet processing industry, the primary objective when designing a coat-hanger die is to achieve a uniform velocity distribution at the exit of the extrusion die outlet. This velocity distribution depends on the internal flow channels of the die, rheological parameters and extrusion process conditions. As a result, coat-hanger dies are often designed for each polymer based on its individual rheological data and other conditions. A multi-rheology method based on a flow network model and the Winter–Fritz equation is proposed and implemented for the calculation, design and optimization of flat sheeting polymer extrusion dies. This method provides a fast and accurate algorithm to obtain die design geometries with constant wall-shear rates and optimal outlet velocity distributions. The geometric design when complemented and validated with fluid flow simulations could be applied for multi-rheological fluid models such as the power-law, Carreau–Yasuda and Cross. This method is applied to sheet dies with both circular- and rectangular-shaped manifolds for several rheological fluids. The designed geometrical parameters are obtained, and the associated fluid simulations are performed to demonstrate its favorable applicability without being limited to only the power-law rheology. The two such designed dies exhibit 32.9 and 21.5 percent improvement in flow uniformity compared to the previous methods for dies with circular and rectangular manifolds, respectively.

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Kutev, Nilolay, and Sonia Tabakova. "Poiseuille flow of Carreau‐Yasuda fluid at variable pressure gradient." ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, April 7, 2024. http://dx.doi.org/10.1002/zamm.202300555.

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AbstractThe unsteady Poiseuille flow of Carreau‐Yasuda fluid in a pipe, caused by a variable pressure gradient, is studied theoretically. As a special case, the steady flow is considered separately. It is proved that at some values of the viscosity model parameters, the problem has a generalized solution, while at others ‐ a classical solution. For the latter, a necessary and sufficient condition is found, which depends on the maximum pressure gradient and the Carreau‐Yasuda model parameters.

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Das, Prosanjit, Sarifuddin, Jyotirmoy Rana, and Prashanta Kumar Mandal. "Unsteady solute dispersion in the presence of reversible and irreversible reactions." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 478, no. 2264 (2022). http://dx.doi.org/10.1098/rspa.2022.0127.

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In an unsteady pulsatile non-Newtonian fluid past a tube with a thin wall layer, the dispersion of a narrow uniform slug of injected solute over a cross-section is examined. At the interface between the mobile fluid phase and the immobile wall phase, both irreversible and reversible reactions have been adopted. The Carreau–Yasuda model is used to describe the fluid’s rheology. The impacts of fluid rheology and reaction parameters on the concentration profiles in the fluid- and wall-phases and the three transport coefficients, viz , the depletion coefficient ( K 0 ) , the convection coefficient ( K 1 ) , the dispersion coefficient ( K 2 ) in the fluid phase are predicted numerically. A considerable shift in the behaviour of K 1 and K 2 with a higher reaction rate may be observed in the transient stage. The axial dispersion of mobile-phase concentration in the unsteady Carreau–Yasuda II fluid model is significantly larger than in Poiseuille and steady Carreau–Yasuda II fluid models, and flow pulsatility on the immobile-phase concentration is prominent upstream at a longer time. In addition, the peak value of the mobile-phase section-mean concentration is consistently lower than in other fluid models. This study could help researchers to understand the drug delivery in blood vessels and pulmonary mechanical ventilation.

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