Relevant bibliographies by topics / Non-Newtonian fluid flows (incl. rheology)

Academic literature on the topic 'Non-Newtonian fluid flows (incl. rheology)'

Author: Grafiati
Published: 10 December 2022
Last updated: 19 February 2023

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Journal articles on the topic "Non-Newtonian fluid flows (incl. rheology)"

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KOPLIK, JOEL, and JAYANTH R. BANAVAR. "MOLECULAR DYNAMICS SIMULATIONS OF NON-NEWTONIAN EXTENSIONAL FLUID FLOWS." International Journal of Modern Physics B 17, no. 01n02 (January 20, 2003): 27–32. http://dx.doi.org/10.1142/s0217979203017047.

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We discuss the use of molecular dynamics computer simulations in the extensional flow dynamics of polymeric, non-Newtonian liquids. The molecular model consists of Lennard-Jones monomers bound into linear chains by FENE potentials, a system known to exhibit characteristic non-Newtonian behavior such as shear thinning and normal stress differences. Here, we simulate liquid bridge flows in which cylinders of such liquids are placed between solid plates and extended to the point of rupture. Measurements of the local fluid stress tensor and interface shape provide information on extensional viscosity and rheology, coupled to microscopic information based on the evolution of molecular configurations. The simulations are in good agreement with laboratory data and with the results of macroscopic numerical calculations where available, but provide new and detailed information on the internal dynamics of liquids in extensional flow.
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Roychowdhury, Souradeep, Rajarshi Chattopadhyay, and Sandip Sarkar. "Thermally developed electrokinetic bi-layer flows of Newtonian and non-Newtonian fluids in a microchannel." Physics of Fluids 34, no. 4 (April 2022): 042011. http://dx.doi.org/10.1063/5.0087355.

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In the present study, thermofluidic characteristics of a combined pressure-driven and electrical field mediated thermally fully developed flow of an immiscible Newtonian and a viscoelastic fluid bi-layer in a microchannel have been analyzed. The simplified Phan-Thien–Tanner model with a linear kernel for the stress coefficient function has been utilized to describe the complex fluid rheology for the non-Newtonian fluid. Disparate zeta potentials have been assumed at the interfaces. Accordingly, distinct zeta potential values have been used at the channel walls and interfaces between the fluids to derive the closed-form analytical expressions for the pertinent velocity, stress, and shear viscosity distributions in the fluid layers. For thermally developed flows, the temperature and entropy distributions are obtained along the microchannel for constant wall heat flux boundary conditions. Major findings from our research show that amplification of the viscoelastic parameter designated by the Weissenberg number exhibits an enhancement in the non-dimensional axial velocity, flow rate, and stress magnitudes. Furthermore, the present study indicates that Joule heating and viscous dissipation significantly vary the dimensionless temperature profiles along the fluid bi-layer. The Nusselt number values are found to decrease with the augmentation of the viscoelasticity, Joule heating, and viscous dissipation parameters. The total entropy generation for the fluid layer systems increases with the increasing Joule heating parameter.
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Arzani, Amirhossein. "Accounting for residence-time in blood rheology models: do we really need non-Newtonian blood flow modelling in large arteries?" Journal of The Royal Society Interface 15, no. 146 (September 2018): 20180486. http://dx.doi.org/10.1098/rsif.2018.0486.

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Patient-specific computational fluid dynamics (CFD) is a promising tool that provides highly resolved haemodynamics information. The choice of blood rheology is an assumption in CFD models that has been subject to extensive debate. Blood is known to exhibit shear-thinning behaviour, and non-Newtonian modelling has been recommended for aneurysmal flows. Current non-Newtonian models ignore rouleaux formation, which is the key player in blood's shear-thinning behaviour. Experimental data suggest that red blood cell aggregation and rouleaux formation require notable red blood cell residence-time (RT) in a low shear rate regime. This study proposes a novel hybrid Newtonian and non-Newtonian rheology model where the shear-thinning behaviour is activated in high RT regions based on experimental data. Image-based abdominal aortic and cerebral aneurysm models are considered and highly resolved CFD simulations are performed using a minimally dissipative solver. Lagrangian particle tracking is used to define a backward particle RT measure and detect stagnant regions with increased rouleaux formation likelihood. Our novel RT-based non-Newtonian model shows a significant reduction in shear-thinning effects and provides haemodynamic results qualitatively identical and quantitatively close to the Newtonian model. Our results have important implications in patient-specific CFD modelling and suggest that non-Newtonian models should be revisited in large artery flows.
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Panasenko, G., K. Pileckas, and B. Vernescu. "Steady state non-Newtonian flow in a thin tube structure: equation on the graph." St. Petersburg Mathematical Journal 33, no. 2 (March 4, 2022): 327–40. http://dx.doi.org/10.1090/spmj/1702.

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The dimension reduction for the viscous flows in thin tube structures leads to equations on the graph for the macroscopic pressure with Kirchhoff type junction conditions at the vertices. Nonlinear equations on the graph generated by the non-Newtonian rheology are treated here. The existence and uniqueness of a solution of this problem is proved. This solution describes the leading term of an asymptotic analysis of the stationary non-Newtonian fluid motion in a thin tube structure with no-slip boundary condition on the lateral boundary.
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VERGUET, STÉPHANE, CHUANHUA DUAN, ALBERT LIAU, VEYSEL BERK, JAMIE H. D. CATE, ARUN MAJUMDAR, and ANDREW J. SZERI. "Mechanics of liquid–liquid interfaces and mixing enhancement in microscale flows." Journal of Fluid Mechanics 652 (May 19, 2010): 207–40. http://dx.doi.org/10.1017/s0022112009994113.

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Experimental work on mixing in microfluidic devices has been of growing importance in recent years. Interest in probing reaction kinetics faster than the minute or hour time scale has intensified research in designing microchannel devices that would allow the reactants to be mixed on a time scale faster than that of the reaction. Particular attention has been paid to the design of microchannels in order to enhance the advection phenomena in these devices. Ultimately, in vitro studies of biological reactions can now be performed in conditions that reflect their native intracellular environments. Liau et al. (Anal. Chem., vol. 77, 2005, p. 7618) have demonstrated a droplet-based microfluidic mixer that induces improved chaotic mixing of crowded solutions in milliseconds due to protrusions (‘bumps’) on the microchannel walls. Liau et al. (2005) have shown it to be possible to mix rapidly plugs of highly concentrated protein solutions such as bovine hemoglobin and bovine serum albumin. The present work concerns an analysis of the underlying mechanisms of shear stress transfer at liquid–liquid interfaces and associated enhanced mixing arising from the protrusions along the channel walls. The role of non-Newtonian rheology and surfactants is also considered within the mixing framework developed by Aref, Ottino and Wiggins in several publications. Specifically, we show that proportional thinning of the carrier fluid lubrication layer at the bumps leads to greater advection velocities within the plugs, which enhances mixing. When the fluid within the plugs is Newtonian, mixing will be enhanced by the bumps if they are sufficiently close to one another. Changing either the rheology of the fluid within the plugs (from Newtonian to non-Newtonian) or modifying the mechanics of the carrier fluid-plug interface (by populating it with insoluble surfactants) alters the mixing enhancement.
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MÁLEK, J., M. RŮŽIČKA, and V. V. SHELUKHIN. "HERSCHEL–BULKLEY FLUIDS: EXISTENCE AND REGULARITY OF STEADY FLOWS." Mathematical Models and Methods in Applied Sciences 15, no. 12 (December 2005): 1845–61. http://dx.doi.org/10.1142/s0218202505000996.

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The equations for steady flows of Herschel–Bulkley fluids are considered and the existence of a weak solution is proved for the Dirichlet boundary-value problem. The rheology of such a fluid is defined by a yield stress τ* and a discontinuous constitutive relation between the Cauchy stress and the symmetric part of the velocity gradient. Such a fluid stiffens if its local stresses do not exceed τ*, and it behaves like a non-Newtonian fluid otherwise. We address here a class of nonlinear fluids which includes shear-thinning p-law fluids with 9/5 < p ≤ 2. The flow equations are formulated in the stress-velocity setting (cf. Ref. 25). Our approach is different from that of Duvaut–Lions (cf. Ref. 10) developed for classical Bingham visco-plastic materials. We do not apply the variational inequality but make use of an approximation of the Herschel–Bulkley fluid with a generalized Newtonian fluid with a continuous constitutive law.
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Avazmohammadi, Reza, and Pedro Ponte Castañeda. "The rheology of non-dilute dispersions of highly deformable viscoelastic particles in Newtonian fluids." Journal of Fluid Mechanics 763 (December 17, 2014): 386–432. http://dx.doi.org/10.1017/jfm.2014.687.

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AbstractWe present a model for the rheological behaviour of non-dilute suspensions of initially spherical viscoelastic particles in viscous fluids under uniform Stokes flow conditions. The particles are assumed to be neutrally buoyant Kelvin–Voigt solids undergoing time-dependent finite deformations and exhibiting generalized neo-Hookean behaviour in their purely elastic limit. We investigate the effects of the shape dynamics and constitutive properties of the viscoelastic particles on the macroscopic rheological behaviour of the suspensions. The proposed model makes use of known homogenization estimates for composite material systems consisting of random distributions of aligned ellipsoidal particles with prescribed two-point correlation functions to generate corresponding estimates for the instantaneous (incremental) response of the suspensions, together with appropriate evolution laws for the relevant microstructural variables. To illustrate the essential features of the model, we consider two special cases: (i) extensional flow and (ii) simple shear flow. For each case, we provide the time-dependent response and, when available, the steady-state solution for the average particle shape and orientation, as well as for the effective viscosity and normal stress differences in the suspensions. The results exhibit shear thickening for extensional flows and shear thinning for simple shear flows, and it is found that the volume fraction and constitutive properties of the particles significantly influence the rheology of the suspensions under both types of flows. In particular, for extensional flows, suspensions of particles with finite extensibility constraints are always found to reach a steady state, while this is only the case at sufficiently low strain rates for suspensions of (less realistic) neo-Hookean particles, as originally reported by Roscoe (J. Fluid Mech., vol. 28, 1967, pp. 273–293) and Gao et al. (J. Fluid Mech., vol. 687, 2011, pp. 209–237). For shear flows, viscoelastic particles with high viscosities can experience a damped oscillatory motion of decreasing amplitude before reaching the steady state.
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Almqvist, T., and R. Larsson. "Some Remarks on the Validity of Reynolds Equation in the Modeling of Lubricant Film Flows on the Surface Roughness Scale." Journal of Tribology 126, no. 4 (October 1, 2004): 703–10. http://dx.doi.org/10.1115/1.1760554.

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The objective of this paper is to investigate the flow in a lubricant film on the surface roughness scale and to compare the numerical solutions obtained by two different solution approaches. This is accomplished firstly by the CFD-approach (computational fluid dynamic approach) where the momentum and continuity equations are solved separately, and secondly the Reynolds equation approach, which is a combination and a simplification of the above equations. The rheology is assumed to be both Newtonian and non-Newtonian. An Eyring model is used in the non-Newtonian case. The result shows that discrepancies between the two approaches may occur, primarily due to a singularity which appears in the momentum equations when the stresses in the lubricant attain magnitudes that are common in EHL. This singularity is not represented by the Reynolds equation. If, however, the rheology is shifted to a non-Newtonian Eyring model the deviations between the two solution approaches is removed or reduced. The second source of discrepancies between the two approaches is the film thickness to wavelength scale ω. It will be shown that the Reynolds equation is valid until this ratio is approximately O10−2.
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Maciel, Geraldo de Freitas, Evandro Fernandes da Cunha, Yuri Taglieri Sao, André Luis Toniati, Guilherme Henrique Fiorot, Fabiana de Oliveira Ferreira, Cláudio Kitano, and Vicente de Paula Gonçalves Junior. "Non-intrusive techniques to measure roll waves level evolving in a flume." E3S Web of Conferences 40 (2018): 05049. http://dx.doi.org/10.1051/e3sconf/20184005049.

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An open-channel experimental set-up is presented in this paper as a tool for examining the presence of instabilities on free-surfaces flows of non-Newtonian fluid. When these flows occur in favorable conditions of inclination, discharge and rheological properties, the propagation of instabilities can evolve into a specific type of wave, known as roll waves. The experimental apparatus developed allows study of stabilized roll waves in many scenarios for non-Newtonian rheology fluids, thereby constituting a highly useful tool for the understanding and control of roll waves. The test fluid used in the experiments was carbopol gel which is rheometrically representative of the muddy material from natural disasters, such as mudflows. Two non-intrusive level measurement systems are proposed (ultrasonic transducer and laser-based absorption technique), and the efficiency of each technique is presented and discussed. Both methods presented relatively low-cost implementation, and calibration procedure assured the quality of the results. The results from the experimental set-up were in agreement in shape and amplitude.
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Liu, Tong, Shiming Zhang, and Moran Wang. "Does Rheology of Bingham Fluid Influence Upscaling of Flow through Tight Porous Media?" Energies 14, no. 3 (January 28, 2021): 680. http://dx.doi.org/10.3390/en14030680.

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Non-Newtonian fluids may cause nonlinear seepage even for a single-phase flow. Through digital rock technologies, the upscaling of this non-Darcy flow can be studied; however, the requirements for scanning resolution and sample size need to be clarified very carefully. This work focuses on Bingham fluid flow in tight porous media by a pore-scale simulation on CT-scanned microstructures of tight sandstones. A bi-viscous model is used to depict the Bingham fluid. The results show that when the Bingham fluid flows through a rock sample, the flowrate increases at a parabolic rate when the pressure gradient is small and then increases linearly with the pressure gradient. As a result, an effective permeability and a start-up pressure gradient can be used to characterize this flow behavior. By conducting flow simulations at varying sample sizes, we obtain the representative element volume (REV) for effective permeability and start-up pressure gradient. It is found that the REV size for the effective permeability is almost the same as that for the absolute permeability of Newtonian fluid. The interesting result is that the REV size for the start-up pressure gradient is much smaller than that for the effective permeability. The results imply that the sample size, which is large enough to reach the REV size for Newtonian fluids, can be used to investigate the Bingham fluids flow through porous media as well.
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Dissertations / Theses on the topic "Non-Newtonian fluid flows (incl. rheology)"

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(9808835), Mohd Kabir. "Flow characteristics of Newtonian and non-Newtonian fluids in a channel with obstruction at the entry." Thesis, 2004. https://figshare.com/articles/thesis/Flow_characteristics_of_Newtonian_and_non-Newtonian_fluids_in_a_channel_with_obstruction_at_the_entry/21721064.

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This study investigates the flow phenomena in a channel with an obstruction at the entry which is placed in another wider parallel walled channel. When obstructed, the flow phenomena inside the channel were observed to be reverse, forward or stagnant depending on the position of the obstruction. The parameters that influence the flow inside and around the test channel are: - the size and shape of the obstruction geometries, the gap between the test channel and the obstruction geometry, the Reynolds number and the length of the test channel. Knowledge of these flow phenomena has the potential benefit in the control of various flows in process engineering applications.

Experimental investigations of these flow parameters were carried out in an open channel rig. Fluids used in the investigations were a Newtonian fluid (water) and two non-Newtonian fluids, namely polyacrylamide solution (0.03% by weight) and mixed solution (xanthan gum, magna floc 139 and magna floc 1011). The polyacrylamide solution and mixed solution had similar viscosity and both show a power-law behavior, however their elastic behavior was different.

Experimental studies of these flows include the velocity measurement and the flow visualization analysis. The velocity measurement provides the quantitative information whereas flow visualization provides the qualitative information of the flow. Numerical simulations of these flow phenomena were also carried out using a CFD software and comparisons are made with the experimental results.

The influence of the size and shapes of the obstruction geometries; and the gap to width (g/w) ratio on the magnitude of the velocity ratio (ViNo: inside/outside velocity of the test channel) was studied. Obstruction geometries used were semicircle, triangle, circle and various shapes of rectangles. The g/w ratios ranging from 0.5 to 8 were selected as a set of distances from the test channel. The influence of the Reynolds numbers on the value of the velocity ratio was investigated. The effect of the test channel length on the velocity ratio was also investigated at the Reynolds number of 2000 for the above specified g/w ratios.

The flow inside the test channel was observed to be forward, reverse or stagnant for both Newtonian fluid (water) and Non-Newtonian fluids. The 'flat plate' obstruction geometry produced the maximum reverse flow inside the test channel compared with other obstruction geometries for both Newtonian and non-Newtonian fluids. The magnitude of the reverse flow for both non-Newtonian fluids used in this study is observed to be half of the magnitude of the reverse flow for water. The maximum reverse flow for non-Newtonian fluids occurs at g/w ratio of 1.0 whereas for Newtonian fluid (water) it occurs at g/w ratio of 1.5.)

The two flow parameters namely, the size and shapes of the obstruction geometries and the gap between the test channel and the obstruction geometries have the strongest influence on the flow phenomena. The Reynolds number has also a strong influence whereas the test channel length has a negligible influence on the flow phenomena.

The numerical simulations using CFD-ACE+ found that the numerically predicted streamlines and velocity vectors of the flow phenomena are in good agreement with the streak lines of the flow visualization images. It was also found that the numerical model used for this study can be generally applied for the prediction of the flow behaviour in the channel with obstruction at the entry.

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(5929685), Vishrut Garg. "Dynamics of Thin Films near Singularities under the Influence of non-Newtonian Rheology." Thesis, 2019.

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Free surface flows where the shape of the interface separating two fluids is unknown apriori are an important area of interest in fluid dynamics. The study of free surface flows such as the breakup and coalescence of drops, and thinning and rupture of films lends itself to a diverse range of industrial applications, such as inkjet printing, crop spraying, foam and emulsion stability, and nanolithography, and helps develop an understanding of natural phenomena such as sea spray generation in oceans, or the dynamics of tear films in our eyes. In free surface flows, singularities are commonly observed in nite time, such as when the radius of a thread goes to zero upon pinchoff or when the thickness of a film becomes zero upon rupture. Dynamics in the vicinity of singularities usually lack a length scale and exhibit self-similarity. In such cases, universal scaling laws that govern the temporal behavior of measurable physical quantities such as the thickness of a lm can be determined from asymptotic analysis and veried by high-resolution experiments and numerical simulations. These scaling laws provide deep insight into the underlying physics, and help delineate the regions of parameter space in which certain forces are dominant, while others are negligible. While the majority of previous works on singularities in free-surface flows deal with Newtonian fluids, many fluids in daily use and industry exhibit non-Newtonian rheology, such as polymer-laden, emulsion, foam, and suspension flows.

The primary goal of this thesis is to investigate the thinning and rupture of thin films of non-Newtonian fluids exhibiting deformation-rate-thinning (power-law) rheology due to attractive intermolecular van der Waals forces. This is accomplished by means of intermediate asymptotic analysis and numerical simulations which utilize a robust Arbitrary Eulerian-Lagrangian (ALE) method that employs the Galerkin/Finite-Element Method for spatial discretization. For thinning of sheets of power-law fluids, a signicant finding is the discovery of a previously undiscovered scaling regime where capillary, viscous and van der Waals forces due to attraction between the surfaces of the sheet, are in balance. For thinning of supported thin films, the breakdown of the lubrication approximation used almost exclusively in the past to study such systems, is shown to occur for films of power-law fluids through theory and conrmed by two dimensional simulations. The universality of scaling laws determined for rupture of supported films is shown by studying the impact of a bubble immersed in a power-law fluid with a solid wall.

Emulsions, which are ne dispersions of drops of one liquid in another immiscible liquid, are commonly encountered in a variety of industries such as food, oil and gas, pharmaceuticals, and chemicals. Stability over a specied time frame is desirable in some applications, such as the shelf life of food products, while rapid separation into its constituent phases is required in others, such as when separating out brine from crude oil. The timescale over which coalescence of two drops of the dispersed phase occurs is crucial in determining emulsion stability. The drainage of a thin film of the outer liquid that forms between the two drops is often the rate limiting step in this process. In this thesis, numerical simulations are used to decode the role played by fluid inertia in causing drop rebound, and the subsequent increase in drainage times, when two drops immersed in a second liquid are brought together due to a compressional flow imposed on the outer liquid. Additionally, the influence of the presence of insoluble surfactants at the drop interface is studied. It is shown that insoluble surfactants cause a dramatic increase in drainage times by two means, by causing drop rebound for small surfactant concentrations, and by partially immobilizing the interface for large surfactant concentrations.
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Books on the topic "Non-Newtonian fluid flows (incl. rheology)"

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Cheremisinoff, Nicholas P. Encyclopedia of Fluid Mechanics, Volume 7: Rheology and Non-Newtonian Flows. Gulf Publishing, 1988.

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Book chapters on the topic "Non-Newtonian fluid flows (incl. rheology)"

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Van Kemenade, Vincent, and Michel Deville. "LEGENDRE SPECTRAL ELEMENTS FOR NON-NEWTONIAN FLUID FLOWS." In Theoretical and Applied Rheology, 310. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-89007-8.50128-3.

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Furbish, David Jon. "Viscous Flows." In Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0016.

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Most flow problems in geology involve viscous fluids which exhibit resistance to shearing motions. Mechanical treatments of such flows therefore must involve a consideration of frictional forces associated with this viscous behavior. Our first objective is to obtain a general equation of motion based on Newton’s second law that involves body and surface forces acting on a fluid element, regardless of the specific fluid involved. The steps in this development are similar to those leading to Euler’s equation for inviscid flows (Chapter 10); the difference is that tangential stresses acting on a fluid element, in addition to normal stresses, are included in the description of surface forces. It will be necessary, when describing normal forces, to distinguish between the thermodynamic pressure p, as used in treating inviscid flows, and a mechanical pressure σ0, which arises in treating viscous effects associated with compressible flows, and flows that simultaneously involve chemical reactions and possibly other phenomena. The second step in obtaining an equation of motion is determined by the specific fluid involved. Here we require a supplemental set of equations that describe the relation between surface forces and rates of fluid strain, as defined by the rate-of-strain tensor examined in Chapter 11. This set of equations, referred to as the constitutive equations of a fluid, varies with fluid rheology. The emphasis of this chapter is on Newtonian fluids. The set of constitutive equations in this case, when coupled with the general equation of motion obtained in the first step, lead to the well known Navier-Stokes equations. In addition, we will briefly examine the case of glacier ice as an example of a non-Newtonian fluid whose rheology is described by Glen’s law (Chapter 3). Treatments of viscous flows that incorporate conservation of energy similarly must involve a consideration of work performed against the frictional effects of viscosity. This performance of work against friction is nonconservative. Its effect therefore is to continuously extract mechanical energy from the main fluid motion, dissipating it in the form of heat. Our treatment of this irreversible conversion of energy will lead to a dissipation function that is added to the energy equation developed in Chapter 9.
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Conference papers on the topic "Non-Newtonian fluid flows (incl. rheology)"

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Niazi, Erfan, Mehrzad Shams, and Goodarz Ahmadi. "Population Balance Modeling for Non-Homogeneous Bubble Column: Effect of Fluid Rheology on Gas Dispersion." In ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72360.

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This work describes the development of a two-dimensional CFD model for gas-liquid flows in a bubble column. Population balance dynamic equation is solved for babbles including bubbles coalescence and break up in the column. Prince and Blanch model for bubbles coalescence extended to non-Newtonian rheology and used in the analysis. Luo and Svendsen model is used for bubbles breakup modeling and the k-e model equations are solved for analysis of primary fluid turbulence. Solutions of carboxy methyl cellulose in water with different concentrations are used as a non-Newtonian pesudoplastic liquid. Raise velocity of bubbles, which play an important role in population balance modeling, is discusses in details for non-Newtonian fluid. As a first step the results for Newtonian bubble column are presented and verified by comparison with the previous studies. Then the effect of changing fluid rheology is discussed in terms of gas volume fraction and continuous liquid velocity.
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Lin, Ruinan, Ke Wang, Qing Li, Narakorn Srinil, and Fangjun Shi. "Experimental Investigation of Flow-Induced Vibration in Gas/Shear-Thinning Liquid Flows in Vertical Pipe." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18162.

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Abstract The non-Newtonian shear-thinning fluid widely exists in the industrial process and the rheology exerts a significant influence on the flow pattern transition and flow-induced vibration (FIV). However, studies on the rheology effect of the liquid phase in the vertical upward two-phase flows are quite lacking due to the complexity of non-Newtonian fluid properties. In the present study, the vertical upward gas/shear-thinning liquid flows experiments are conducted on a rigid acrylic pipe with an internal diameter of 20 mm. Three different Carboxymethyl Cellulose (CMC) solutions are used as the non-Newtonian fluid, aimed at capturing a two-phase flow regime transition including the vertical slug, churn and annular flows. The results indicate that the maximum energy spectral densities of vibration occur at the slug-to-churn flow transition boundary at low liquid velocities and the annular flow region under high liquid velocities, respectively. The effects of the rheology of the shear-thinning fluid in terms of the flow patterns and FIV are also presented and discussed.
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Gray, Jonathan D., Ieuan Owen, and Marcel P. Escudier. "An Experimental Study of the Effects of Non-Newtonian Blood Rheology in a Large Scale Model of a Distal Anastomosis." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/bed-23137.

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Abstract This paper is concerned with determining experimentally the extent to which the assumption of blood being a Newtonian fluid affects the flow through a distal anastomosis. While many authors studying vascular fluid mechanics are turning their attention to geometrical considerations, the importance of the non-Newtonian effect is still unclear, and has yet to be experimentally quantified for anastomotic flows. The study reported in this paper aims to address the problems inherent in any comparison between a Newtonian and non-Newtonian flow by investigating qualitative Reynolds number trends in the flow characteristics for both types of fluid. Estimates are then made regarding the quantitative differences that may be expected when using a Newtonian fluid to represent blood flow through an anastomosis.
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Hammad, Khaled J. "Heat Transfer in Annular Shear-Thinning Non-Newtonian Flows Over a Sudden Pipe Expansion." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66171.

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Non-isothermal suddenly expanding annular pipe flows of a shear-thinning non-Newtonian fluid are numerically studied within the steady laminar flow regime. The power-law constitutive equation is used to model the shear-thinning rheology of interest. A parametric study is performed to reveal the influence of annular-nozzle-diameter-ratio, k, power-law index, n, and Prandtl numbers over the following range of parameters: k = {0, 0.5}; n = {1, 0.6}; and Pr = {1, 10, 100}. Heat transfer enhancement, i.e., wall heat transfer rates higher than the fully developed ones downstream of the expansion plane, is observed only for Pr = 10 and 100. In the case of Pr = 1, wall heat transfer rates monotonically increase to the fully developed value. Higher Pr, k, and n values, in general, result in more significant heat transfer enhancement downstream of the expansion plane. Further, shear-thinning non-Newtonian flows display two local peak wall heat transfer rates, in comparison with only one peak value in the case of Newtonian flows.
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Podryabinkin, Evgeny, Valery Rudyak, Andrey Gavrilov, and Roland May. "Detailed Modeling of Drilling Fluid Flow in a Wellbore Annulus While Drilling." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-11031.

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To produce a well safely, the wellbore pressure during drilling must be in a range that prevents collapse yet avoids fracturing. This range is often called “the operating window”. Exceeding the limits of this range can trigger wellbore instability or initiate well control incidents. Pressure prediction requires an understanding of the hydrodynamics processes that occur in a borehole while drilling. Describing these processes is complicated by many factors: the mud rheology is usually non-Newtonian, the flow mode can be laminar or turbulent, and the drillstring can rotate and be positioned eccentrically. Known semi-analytical approaches cannot account for the full range of fluid flows that can arise during drilling. These techniques don’t take into account all factors. Accurate numerical simulation of the flow of drilling fluids is a means to describe the fluid behavior in detail. For numerical solutions of hydrodynamics equations a unique algorithm based on a finite-volume method and a new model of turbulence for non-Newtonian fluids was developed. The model considers string rotation and eccentricity of the drillstring. Newtonian and non-Newtonian fluids as described by the Herschel–Bulkley rheological model have been implemented. Data obtained via systematic parameter studies of the flow in a borehole are available for fast determination of parameters like pressure drop, velocity field, and stresses corresponding to any drilling condition. Applying the new model for the annulus flow and comparing the results to the parallel plate flow approximation enabled us to quantify the error made due to the approximated solution for non-Newtonian fluid rheology. The difference between the solutions grows as the annular gap increases. This situation is a function of the rheological parameters. Secondary flow effects can only be seen when applying the new solution method.
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Metwally, Hossam M., and Raj M. Manglik. "A Computational Study of Enhanced Heat Transfer in Laminar Flows of Non-Newtonian Fluids in Corrugated-Plate Channels." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1277.

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Abstract The enhanced heat transfer behavior of laminar shear-thinning, power-law fluid flows in sinusoidal corrugated-plate channels is investigated. With duct plates at uniform wall temperature, periodically developed flows are considered for a wide range of channel corrugation aspect ratio (0 ≤ γ ≤ 1), flow rates (10 ≤ Reg ≤ 1500), and pseudo-plastic flow behavior indices (n = 0.5, 0.8, and 1.0). Typical velocity and temperature distributions, along with extended results for isothermal friction factor f and Collburn factor j are presented. The enhanced forced convection is found to be strongly influenced by γ, and the flow field displays two distinct regimes: undisturbed laminar or no swirl, and swirl flow regimes. In the no-swirl regime, behavior similar to that in fully developed straight duct flows with no cross-stream disturbance is obtained. The shear-thinning nature of the fluid, however, decreases f and enhances j. In the swirl regime, flow separation and reattachment in the corrugation troughs generates transverse vortices that grow with Reg and γ. The transition to this regime is also seen to depend on Reg, γ, and n, and in shear-thinning flows, it occurs at a lower Reg. The combined effects of corrugated plate geometry and non-Newtonian fluid rheology produce a heat transfer enhancement, as measured by the factor j/f, of over 3.3 times that in a flat-plate channel depending upon γ, n, and Reg.
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7

Usha, R., S. Millet, H. BenHadid, and F. Rousset. "Stability of a Shear-Thinning Film on a Porous Substrate." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30464.

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A significant feature of gravity-driven film flows of Newtonian and rheologically complex fluids down an inclined/vertical substrate is the instability of the free surface which manifests as surface waves having wavelengths much larger than the film thickness. There are a number of applications which can be modeled as thin film flow systems on porous substrates. Pascal [1] investigated the stability of a falling power-law film on an inclined porous substrate. This model for the fluid predicts a viscosity that goes to infinity as the shear rate approaches zero. There is a need to employ a more appropriate model to examine the effects of non-Newtonian rheology on the dynamics and stability of thin film free surface flows down inclined or vertical rigid/porous substrates. The four-parameter Carreau model predicts a viscosity that remains finite as the shear rate approaches zero and is given by η−η∞η0−η∞=[1+(δγ)˙2]n−12.(1) Weinstein [2] and Rousset et al. [3] have considered the Carreau model and have examined the temporal stability of a film flow down an impermeable rigid inclined substrate. The authors show that a shear-thinning Carreau fluid film on a rigid impermeable substrate is more unstable than a Newtonian film. This calls for an analysis that includes both the effects of Carreau non-Newtonian rheology and bottom permeability and the present study reports such an investigation of a Carreau non-Newtonian film on a porous inclined substrate.
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8

Bossio, Boris M., Armando J. Blanco, and Franz H. Herna´ndez. "Eulerian-Eulerian Modeling of Non-Newtonian Slurries Flow in Horizontal Pipes." In ASME 2009 Fluids Engineering Division Summer Meeting. ASMEDC, 2009. http://dx.doi.org/10.1115/fedsm2009-78019.

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Slurries transport through circular pipelines is present in many industries: oil, mineral, water and others. There are many variables involved in slurry flows, causing the flow behavior of these slurry systems to vary over a wide range, and therefore, different approaches have been used to describe their behavior in various flow regimes. At some typical applications, the rheology of the base fluid is itself non-Newtonian. Due to the wide range of variables and their variations, the experimental approach is necessarily limited by geometric and physical scale factors. For a non-Newtonian base fluid, only some particular cases that cover a limited range of conditions have been reported. For these reasons, numerical simulation constitutes an ideal technique for predicting the general flow behavior of these systems. Models in this area can be divided in two different classes: Eulerian-Eulerian and Lagrangian-Eulerian. Lagrangian-Eulerian models calculate the path and motion of each particle, while Eulerian-Eulerian models treat the particle phase as a continuum and average out motion on the scale of individual particles. This work focuses on the Eulerian-Eulerian approach for modeling the flow of a mixture of sand particles and a non-Newtonian fluid in a horizontal pipe. The steady-state rheological behavior of the base fluid was expressed by the three-parameter Sisko model. Homogeneous and heterogeneous flow regimes are considered. For the present study, the widely used “k-ε model” is employed to model turbulent viscosity. The k-ε turbulence model introduces two additional variables: the kinetic energy of the fluid turbulence, k, and the dissipation rate of this kinetic energy, ε. These two variables are solved throughout the fluid domain via two additional differential transport equations. The k-ε model is therefore commonly referred to as a “two-equation” turbulence model. The turbulent viscosity is then determined as a function of k and ε. Additionally, closure of solid-phase momentum equations requires a description for the solid-phase stress. Constitutive relations for the solid-phase stress, considering the inelastic nature of particle collisions based on kinetic theory concepts, have been used. Governing equations were solved numerically using the control volume-based finite element method. An unstructured non-uniform grid was chosen to cover the entire computational domain. A second-order scheme in space was used. Precise numerical solutions in a fully developed turbulent flow were found. Flow behavior for different sand concentrations was simulated. Results for the mean pressure gradients were compared with experimental data. The results turned out to be in compliance with those from the experimental data, for a sand concentration of less than 5%. Numerical simulations of non-Newtonian slurry flows provide a method that can relate properties of the fluid and solid component of the slurry, and does not entail the time and expenses needed for empirical studies. This also might provide a further sight to develop correlations between mean pressure gradients and slurry mean velocity.
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9

Chatterjee, Ajay, and Fatemeh Khalkhal. "Stability and Scalar Transport in Laminar Non-Newtonian Flow in a Bifurcating T-Junction." In ASME 2019 17th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/icnmm2019-4274.

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Abstract We consider the prototype bifurcating T-junction planar flow and compare the stability of the steady two-dimensional flow field for a Newtonian and a shear thinning inelastic fluid. Global stability of the flow to two-dimensional perturbations is analyzed using numerical solutions of the linear perturbation equation. Calculations are performed for two flow ratios between the main channel and the bifurcating channel, and for two different values of the time constant in the non-Newtonian rheological model. The results show that although the steady flow remains stable to two-dimensional perturbations for Newtonian Reynolds number up to ∼ 400, shear thinning is destabilizing in that the decay rate of the perturbation field is slower. The perturbation growth rate curves for all of the different cases may be correlated by volume averaging the local Reynolds number over the flow domain, indicating that the effect of shear thinning on stability may be described using a suitably defined average Reynolds number. These stability results provide some justification for CFD calculations of steady non-Newtonian two-dimensional flows presented in earlier papers. Since scalar transport is of interest in this flow field, we also present some numerical calculations for the Nusselt number profile along the bifurcating channel wall. The results show that for the shear thinning fluid the scalar transport rate is differentially larger by ∼ 75% across one of the bifurcating channel walls, a consequence of fluid rheology enhancing the effect of flow asymmetry in the entrance region of the bifurcation.
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10

Kim, Yong Hyun, Goddy Chungag, Joon Sang Lee, Emmanuel Ayorinde, and Xin Wu. "Studies on Blood Rheology in a Coronary Artery Using CFD Technique With an AE Sensor." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43431.

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There still exists a need for developing more accurate generalized models for multiscale biofluids systems that enable clearer understanding of normal microcirculation and complexities of disease hemorheology. Such work will yield enhanced computational and experimental techniques for a wider class of flows having fluid-solid interactions, complex moving boundaries, and involving red blood cell (RBC) aggregation under physiological conditions. The work reported here has involved the multiphase non-Newtonian fluid simulations of pulsatile flow in an idealized coronary artery model have been performed using numerical and experimental studies. The secondary flow affected a local RBC accumulation on the inside curvature and it changed the local flow characteristics as well. RBC viscosity and wall shear stress (WSS) were changed with a function of local hemotocrit. In practical work involving specialized velocity measurement and acoustic emission monitoring of flow characteristics, flow-induced vibration effects, as well as material and physiological aspects of arterial systems were conducted. Computations of arterial flows were made and experimental investigations using glass microtube simulations of arteries were carried out. This work contributes to an understanding of the mechanics of relationship between the progression of certain inherited diseases and the mechanical deformation characteristics of the arterial system and the RBC.
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