non-Newtonian Flow Research Articles

Non-Newtonian lacuno-canalicular fluid flow in bone altered by mechanical loading and magnetic field

As humans age, they experience deformity and a decrease in their bone strength, such brittleness in the bones ultimately lead to bone fracture. Magnetic field exposure combined with physical exercise may be useful in mitigating age-related bone loss by improving the canalicular fluid motion within the bone’s lacuno-canalicular system (LCS). Nevertheless, an adequate amount of fluid induced shear stress is necessary for the bone mechano-transduction and solute transport in the case of brittle bone diseases. The underlying mechanisms of how magnetic fields, in combination to mechanical loading, affects the canalicular fluid motion still need to be explored. Accordingly, this study aims to develop a computer model to investigate the role of magnetic fields on loading-induced canalicular fluid flow in a curvy lacunar canalicular space with irregular osteocyte cell processes and walls. Moreover, this study considers canalicular fluid as non-Newtonian fluid, i.e., Jeffery fluid. In addition, a machine learning model was further employed for the estimation of parameters which significantly influence the canalicular fluid flow in response to loading and magnetic field. The results show that static magnetic field modulates the loading-induced canalicular fluid flow. Additionally, present study accelerates the fluid induced wall shear stress in case of osteoporosis.

Study of Gas–Liquid Two-Phase Flow Characteristics at the Pore Scale Based on the VOF Model

To study the effects of liquid properties and interface parameters on gas–liquid two-phase flow in porous media. The volume flow model of gas–liquid two-phase flow in porous media was established, and the interface of the two-phase flow was reconstructed by tracing the phase fraction. The microscopic imbibition flow model was established, and the accuracy of the model was verified by comparing the simulation results with the classical capillary imbibition model. The flow characteristics in the fracturing process and backflow process were analyzed. The influence of flow parameters and interface parameters on gas flow was studied using the single-factor variable method. The results show that more than 90% of the flowing channels are invaded by fracturing fluid, and only about 50% of the fluid is displaced in the flowback process. Changes in flow velocity and wetting angle significantly affect Newtonian flow behavior, while variations in surface tension have a pronounced effect on non-Newtonian fluid flow. The relative position of gas breakthrough in porous media is an inherent property of porous media, which does not change with fluid properties and flow parameters.

Impacts of thermal conductivity and viscosity variation parameters on non-Newtonian nanofluid flow with mixed convection and chemical reaction features

Mixed convection Couette flow of biviscosity nanofluid is constructed in the presence of viscosity and thermal conductivity variation parameters. A flow is affected by chemical reactions and heat sources. Using a combination of thermophoresis and Brownian motion features, Buongiorno's framework for nanofluids was used to establish mathematical formulas related to flow, heat/mass transfer under the impact of viscous dissipation, double viscosity, and thermal conductivity fluctuation. Governing equation describes the fluid model in a system of ordinary differential equations (ODEs), and then non-dimensional quantities and Boussinesq’s approximations are used to obtain a new system of ODEs. The leading system’s results are constructed by a semi-analytical method called homotopy perturbation method (HPM). All obtained graphical results are proposed in terms of y versus different physical quantities of fluid distributions. Outcomes show that the growth in variable thermal conductivity causes a reduction in fluid velocity and temperature, while it causes a rise in nanoparticle concentration. Applications like lubrication, drug carriers and polymer processing can get more opportunities through studies of the present system.

Numerical simulation of a non-Newtonian nanofluid on mixed convection in a rectangular enclosure with two rotating cylinders

Non-Newtonian fluid flows are a present advancement in industrial heat transfer and fluid mechanics, with numerous applications in engineering field as well as in real life such as food industry, petroleum refiners, biological processes, biomedical engineering, chemical engineering, etc. As a result, this numerical investigation explore the heat transfer and fluid flow behaviour of a mixed convective non-Newtonian power-law nanofluid ( Al 2 O 3 - H 2 O ) in a rectangular enclosure. The physical model is considered as a two-dimensional rectangular enclosure consisting two rotating hot cylinders ( T H )in the middle part of the cavity, where one moving clockwise and the other counter-clockwise directions. The left and right walls of the chamber are taken relatively low temperature ( T C ) while the remaining top and bottom walls are insulated. The important thermophysical property, viscosity, depends on the fluid shear rate, and the thermal conductivity depends on the fluid temperature. The related governing equations are solved by using the finite element method, and to describe the response surfaces the response surface methodology (RSM) is applied. The influence of the relevant non-dimensional parameters, Prandtl number ( Pr = 6.2 ), Reynolds number ( Re = 10 , 100, 200 and 400), power-law index (n = 0.6, 0.8, 1.0 and 1.4), Richardson number ( Ri = 1.0 , 2.0, 4.0 and 6.0), and nanoparticle volume fraction ( ϕ = 0.00 , 0.01, 0.02 and 0.04), are explained with physical interpretation by using streamlines, isotherm lines, velocity profile, temperature profile, and average Nusselt number ( Nu av ). To visualise the response surfaces, 2D and 3D contour plots are explained using the RSM. It is concluded that by adding nanoparticle into base fluid, the rate of heat transfer developed significantly. Same phenomena exhibits for larger magnitudes of Ri and Re . And, by increasing the value of n from 0.6 to 1.4, the Nu av would go down by 39.8 percent.

COMPUTATIONAL ANALYSIS OF FLUID-STRUCTURE INTERACTION AND HEAT TRANSFER IN EXTRUSION PROCESSES

The extrusion process is integral to manufacturing, enabling the production of continuous profiles with precise cross-sections for various industries, including automotive, construction, and aerospace. This study focuses on the computational analysis of material flow and heat transfer during the extrusion of an L-type section under steady-state conditions. Finite element analysis is used to model the extrusion process.The research evaluates the impact of key parameters such as container temperature, ram velocity, and friction coefficients on the billets thermal profile and exit temperature. The study incorporates non-Newtonian flow dynamics, and thermal coupling to provide comprehensive insights into optimizing process efficiency, die design, and material flow uniformity. The results demonstrate the critical role of thermal and frictional parameters in enhancing extrusion quality and preventing material defects.

Computational Fluid Dynamics Simulation and Analysis of Non-Newtonian Drilling Fluid Flow and Cuttings Transport in an Eccentric Annulus

This study examines the flow behavior as well as the cuttings transport of non-Newtonian drilling fluid in the geometry of an eccentric annulus, accounting for what impacts drill pipe rotation might have on fluid velocity, as well as annular eccentricity on axial and tangential distributions of velocity. A two-phase Eulerian–Eulerian model was developed by using computational fluid dynamics to simulate drilling fluid flow and cuttings transport. The kinetic theory of granular flow was used to study the dynamics and interactions of cuttings transport. Non-Newtonian fluid properties were modeled using power law and Bingham plastic formulations. The simulation results demonstrated a marked improvement in efficiency, as much as 45%, in transport by increasing the fluid inlet velocity from 0.54 m/s to 2.76 m/s, reducing the amount of particle accumulation and changing axial and tangential velocity profiles dramatically, particularly at narrow annular gaps. At a 300 rpm rotation, the drill pipe brought on a spiral flow pattern, which penetrated tangential velocities in the narrow gap that had increased transport efficiency to almost 30% more. Shear-thinning behavior characterizes fluid of which the viscosity, at nearly 50% that of the central core low-shear regions, was closer to the wall high-shear regions. Fluid velocity and drill pipe rotation play a crucial role in optimizing cuttings transport. Higher fluid velocities with controlled drill pipe rotation enhance cuttings removal and prevent particle build-up, thereby giving very useful guidance on how to clean the wellbore efficiently in drilling operations.

Analytical Study of Blood Flow through a Tapered Stenosed Artery: Impact of Arterial Shape on Fluid Dynamics

This study presents an analytical investigation into the dynamics of blood flow through a tapered stenosed artery, focusing on the influence of arterial shape on fluid dynamics. The arterial medium is modeled as a power law fluid. Governing equations for laminar, incompressible, and non-Newtonian fluid flow subject to appropriate boundary conditions are solved. Perturbation mathematical method has used to get the analytical expressions. Equations are derived for key flow parameters, including velocity components, volumetric flow rate, wall shear stress, and pressure gradient. The findings reveal significant insights into the impact of arterial shape on fluid dynamics, highlighting how variations in artery geometry affect velocity profiles, pressure gradients, and wall shear stress distributions. Specifically, the study observes notable changes in wall shear stress with alterations in the tapering angle of artery. This research contributes to a deeper understanding of the complex interplay between arterial geometry and blood flow dynamics, with implications for diagnosis and treatment of vascular diseases.

Analyzing the impact of non-Newtonian nanofluid flow on pollutant discharge concentration in wastewater management using an artificial computing approach

Wastewater discharge is important in numerous areas of industries and in governance of the environmental sectors. Controlling and monitoring water pollution are essential for protecting the availability of water and upholding standards of sustainability. Thus, in the current study, the effects of pollutant discharge concentration (PDC) are considered while analyzing the flow of non-Newtonian nanofluids (NNNF) through the permeable Riga surface subject to heat radiation. Walter’s B fluid (WBF) and second-grade fluids (SGFs), two distinct types of NNNF, have been investigated. The fluid flow is expressed as a system of PDEs, which are simplified into lower order by employing similarity approach. These equations (ODEs) are solved using the Levenberg Marquardt back-propagation optimization algorithm (LMBOA) of the artificial neural network (ANN). The Matlab package “bvp4c” is used for generating the dataset in order to validate the results of the ANN-LMBOA. The dataset was developed for various flow scenarios, as well as ANN evaluation and validation. The accuracy of the ANN-LMBOA model is estimated though numerous statistical tools, i.e., histogram, regression measures, curve fitting, performance plots, and validation tables. The numerical outcomes of bvp4c package are also compared to the published literature. Which show best accuracy and resemblance with each other for the limiting case. The targeted date absolute error is accomplished within the range of 10–4-10–5 which confirms the outstanding accuracy of ANN-LMBOA. It is concluded form error histograms (EHs) that the EHs values for case 1–4 is lie about 3·6×10-7, 7·83×10-9, -4.7×10-8 and -2·9×10-6 respectively.

Time - Dependent Magnetohydrodynamic Non-Newtonian Nanofluid Flow with Lorentz Force, Viscous Dissipation and Thermophoresis Between Parallel Plates

The study examined a three-dimensional unsteady Magnetohydrodynamic non-Newtonian nanofluid flow with magnetic induction, Lorentz force, viscous dissipation and thermophoresis between two parallel horizontal plates. In this study, fluid’s dynamic viscosity and thermal conductivity parameters have been assumed to vary depending on temperature changes. The density has been assumed to be incompressible and also the study assumes that the gravitational effects are negligible. The governing equations: continuity, Navier-Stokes, Energy, Magnetic Induction and Concentration equations for the non-Newtonian nanofluid flow have been developed and non-dimensionalized. Dimensionless parameters arising from the dimensionless equations have also been determined. Finite difference numerical approximation method has been used to approximate the systems of the governing equations in difference form. Profiles for the flow variables have been presented and discussed. Results show that increasing thermophoresis parameter increases the specie concentration while increasing Schmidt number and chemical reaction parameter reduces concentration profiles. Magnetic induction profiles rise with an increase in Reynolds number but declines with an increase in magnetic Prandtl number. Temperature and velocity profiles increase with an increase in Reynolds number. The study of electrically conducting fluids with the consideration of Lorentz force, thermophoresis, viscous dissipation, chemical reaction, variable dynamic viscosity, variable thermal conductivity and magnetic induction is very useful in designing heat and mass transfer appliances. It is also significant in cooling and overheating control systems.

Fractal dimension of non-Newtonian Hele-Shaw flow subject to Saffman-Taylor instability

Fractal dimension of non-Newtonian Hele-Shaw flow subject to Saffman-Taylor instability

Rheological, microbiological, and in vitro digestive properties of Kefir produced with different Kefir grains and commercial starter cultures.

This research investigates the production of kefir using Turkish and Kazakh kefir grains and commercial starter cultures, followed by storage at 4 °C for 30 days. The study monitors the rheological properties and microbiological characteristics of kefir on the 1st, 15th, and 30th days of storage, as well as during dynamic in vitro gastrointestinal digestion. Kefir samples were passed through a dynamic in vitro gastrointestinal model simulating the digestive processes of the mouth, stomach, and small intestine which was designed in laboratory conditions. Kefir from Turkish kefir grain exhibited the lowest average titratable acidity, apparent viscosity, and flow behavior index, while kefir from Kazakh kefir grain had the highest average pH. Over the storage period, pH and flow behavior index decreased, while titratable acidity, viscosity, and consistency coefficient increased. The kefir samples showed non-Newtonian pseudoplastic flow characteristics. The acetic acid bacteria and Leuconostoc counts of kefir samples produced with commercial starter cultures were higher than those produced with kefir grains, while yeast counts were higher in kefir samples produced with kefir grains. During storage and in vitro gastrointestinal digestion, the number of microorganisms in kefir samples decreased. Turkish kefir grain resulted in the lowest reduction (%) of microorganism counts during in vitro gastrointestinal digestion. These findings shed light on the rheological, microbiological, and in vitro digestive properties of kefir during storage, which may contribute to improving the quality and health benefits of kefir products. The present study revealed that the kefir produced with kefir grains had a lower decrease in the viability of microorganisms compared to the kefir produced with starter culture after passage through the gastrointestinal model, so kefir produced with kefir grains may be more preferred due to its possible health benefits.

A new non-segregated numerical method for non-Newtonian viscoelastic flows

A new non-segregated numerical method for non-Newtonian viscoelastic flows

A shear and elongational decomposition approach of the rate-of-deformation tensor for non-Newtonian flows with mixed kinematics

We propose a novel approach for non-Newtonian viscoelastic steady flows based on a decomposition of the rate-of-deformation tensor which here, in a simplified version, leads to an anisotropic generalised Newtonian fluid-like model with separated treatment of kinematics pertaining to shear and extensional flows. Care is taken to assure that the approach is objective and does not introduce spurious effects due to dependence on a specific reference frame. This is done by separating the rate-of-deformation tensor into shear and elongational components, with the local scalar shear and elongation rates being the second invariant of each tensor separately, and by modifying the method used to separate the rate-of-deformation tensor so that it becomes independent of superimposed rigid rotations, thus satisfying the principle of material indifference. We assess the model with two test cases: planar contraction flow, often employed to evaluate numerical methods or constitutive equations and for which experimentally observed corner vortex enhancement and pressure drop increase are seldom found in numerical simulations; and flow past confined or unconfined cylinders, for which experiments indicate a drag increase due to elasticity and most predictions give a drag decrease. With our anisotropic model, incorporating additional elongational-flow-related terms, large vortices and accentuated pressure drop coefficients can be predicted for the contraction problem and enhanced drag coefficient for the cylinder problems. This is the first work where problems of non-Newtonian fluid mechanics are solved numerically with separation of strain rate into shear and elongational components.

Mechanical Behavior of Flexible Fiber Assemblies: Review and Future Perspectives.

Flexible fibers, such as biomass particles and glass fibers, are critical raw materials in the energy and composites industries. Assemblies of the fibers show strong interlocking, non-Newtonian and compressible flows, intermittent avalanches, and high energy dissipation rates due to their elongation and flexibility. Conventional mechanical theories developed for regular granular materials, such as dry sands and pharmaceutical powders, are often unsuitable for modeling flexible fibers, which exhibit more complex mechanical behaviors. This article provides a comprehensive review of the current state of research on the mechanics of flexible fiber assemblies, focusing on their behavior under compression, shear flow, and gas-fiber two-phase flow processes. Finally, the paper discusses open issues and future directions, highlighting the need for advancements in granular theories to better accommodate the unique characteristics of flexible fibers, and suggesting potential strategies for improving their handling in industrial applications.

Design of Trabecular Bone Mimicking Voronoi Lattice-Based Scaffolds and CFD Modelling of Non-Newtonian Power Law Blood Flow Behaviour

Design of Trabecular Bone Mimicking Voronoi Lattice-Based Scaffolds and CFD Modelling of Non-Newtonian Power Law Blood Flow Behaviour

A position-based PFEM formulation for free-surface non-Newtonian flows with application to fresh concrete

This work presents a methodology for free surface non-Newtonian incompressible flows using a particle position-based formulation of the Particle Finite Element Method (PFEM) [1], motivated by the simulation of fresh concrete flow. This method is based on the Lagrangian description of the flow and represents the fluid domain by cloud of particles, with a finite element mesh being built, taking the particles as nodes, to solve the motion equations and update the particle positions. To deal with large distortions of fluid flows, such mesh is constantly rebuilt, leading to a method very robust to deal with topological changes within the fluid domain. This approach requires updating the reference configuration, enabling the use of partially or fully updated Lagrangian descriptions. The weak solution is based on the stationary energy principle considering current nodal positions and pressures as variational parameters, deviating from the common practice of employing velocity and pressure as unknowns. Furthermore, smoothed versions of the Bingham and Herschel-Bulkley viscoplastic models are chosen to represent the fresh concrete behavior, keeping stresses independent of strain history and making updating the reference for the fluid simple, without the need for considering the stress distribution in the past reference. The implicit α-generalized strategy is chosen for time integration, enabling second order convergence and ensuring good stability due to the control over numerical dissipation at high frequencies. Finally, selected 2D and 3D examples are simulated to test and verify the proposed methodology.[1] IDELSOHN, S. R.; ONATE, E.; Del Pin, F. The particle finite element method: a powerful tool to solve incompressible flows with free-surfaces and breaking waves. International Journal for Numerical Methods in Engineering, John Wiley and Sons, Ltd, v. 61, n. 7, p. 964–989, oct 2004. ISSN 1097-0207.

Simulation of 3D concrete printing using an implicit formulation of the moving particle semi-implicit method

Additive construction techniques, such as 3D Concrete Printing (3DCP), offer significant advantages, as reduced material waste, optimized construction times, and the possibility to create complex shapes that would be difficult to achieve through conventional methods. Despite the advances in 3DCP, some challenges persist due to the still incipient development to predict the printing results. The fresh properties of the material play a crucial role. Therefore, in addition to experimental studies, numerical modeling emerges as a valuable tool to investigate the dynamic aspects of the extrusion process in 3DCP. However, the numerical modeling of 3DCP is challenging due to the complex rheological behavior of the self-supporting concrete, which typically exhibits high values of apparent viscosity at low deformation rates. To address these challenges, we adopted the moving particle semi-implicit (MPS) method, which is a particle-based simulation technique suitable for modeling free surface flows and materials undergoing large deformations. As a Lagrangian approach, MPS discretizes the computational domain into particles that move according to the governing equations of fluid motion. The conventional formulation of the MPS presents numerical restrictions when dealing with highly viscous fluids. To assure numerical stability, the semi-implicit approach requires very low time steps, resulting in high processing costs. In this way, this study adopts an implicit algorithm that allows for significantly larger time steps, resulting in reduced processing time compared to the conventional semi-implicit formulation. To validate the implicit algorithm, simulations of non-Newtonian flow between parallel plates were validated using analytical solutions, demonstrating better accuracy at lower Bingham numbers. The 3DCP simulations were conducted to describe the flow of fresh mortar using the Bingham-Papanastasiou constitutive model. The geometry of the 3D model includes the extrusion nozzle and a planar surface where concrete is printed. The numerical investigation involved simulations with different nozzle heights (Hn), printing speeds (V), and extrusion volumetric fluxes (U). The cross-sectional shapes of the extruded layers were compared with experimental data, showing qualitative agreement. The results demonstrate the potential of the implicit MPS method for modeling 3DCP processes.

Impact of Hall current on radiative Ree-Eyring nanofluid flow across rectangular frame with Joule and viscous dissipation effects

Fluid flow and heat transfer inside a rectangular framework have numerous engineering applications, including energy generation, power systems, cooling technologies, and nuclear reactors. Researchers are currently focusing on improving heat transfer rates through the use of nanofluids. With this motive, the current study investigates the constant, incompressible flow of nanofluids containing copper nanoparticles suspended in ethylene glycol and water, within a rectangular framework. The study investigates the non-Newtonian Ree-Eyring nanofluid flow with impact of Hall Effects. Furthermore, the impacts of Joule dissipation, thermal radiation, and viscous dissipation are examined. Additionally, the physical quantities skin friction coefficient and Nusselt number are investigated. The mathematical modeling is examined, followed by the application of similarity transformation to the nonlinear governing partial differential equations (PDEs) with particular boundary conditions. This procedure simplifies the derivation of dimensionless ordinary differential equations. The dimensionless scheme of equations is then solved numerically using the bvp4c numerical technique, which is integrated into the MATLAB software. Graphical and tubular representations are used to study the logical impact of fascinating aspects on subjective dimensions. According to the findings, greater magnetic parameters reduce velocity components, whereas larger Ree-Eyring fluid values enhance them. The temperature profile improves when magnetic parameters increase, but declines as Ree-Eyring fluid parameters rise. As suction parameters increase, the skin friction coefficient drops. The Nusselt number drops with a rising Biot number. This study have examined the first time to the best of authors knowledge.

Computational study on entropy generation in Casson nanofluid flow with motile gyrotactic microorganisms using finite difference method

The present study reveals the phenomenon of flow and thermal variations of non-Newtonian nanofluids flow of Copper (Cu) nanoparticles through two orthogonal permeable porous discs. Additionally, the study delves into the significance of liquid solid interfacial layer and nanoparticle diameter is studied to optimize the thermal conductivity. Gyrotactic Microorganisms are also considered to optimize the nanoparticles stability inside the fluid, and the entropy generation caused to system disorder, so entropy analysis is also calculated. Using appropriate dimensionless variables, the controlling PDEs are converted into dimensionless forms. These dimensionless PDEs are solved using the Finite Difference technique, which yields very accurate and stable solutions. Higher values of the Rayleigh bio-convection and mixed convection terms enhance the flow velocity field in both porous discs. The less thickness of nanolayer has significance effect to optimize the temperature. Enhancing the values of bioconvection Lewis number leads to a decrease in motile microorganism concentration in both permeable discs, and entropy generation rate increases against rising power of Eckert number and thermal radiation rise. The finite difference method outcomes have been thoroughly validated against already published research, and showing an excellent correlation. This research holds significant potential for applications in the fabrication and electromagnetic control of advanced magnetic nanofluid materials, relevant to biomedical, energy, thermal management, and aerospace technologies.

Fluid–structure interaction in a follow-up study of arterio-venous fistula maturation

Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysed patients. AVF is created surgically using the patient’s artery and vein. Once the connection (anastomosis) is made, the maturation process begins. Studies have shown that most AVFs do not survive beyond one year. This study presents fluid–structure interaction (FSI) modelling of non-Newtonian blood flow through an end-to-side radio-cephalic AVF, investigated weekly during a 15-week follow-up period and 1.5 years postoperatively using ultrasound methods. The aim was to collect qualitative and quantitative data regarding changes in hemodynamics and alterations in the walls of AVF vasculature. Different material properties were assigned to the artery, suture zone (anastomosis), and vein, while the stiffening of the venous arm over time was also modelled. The proposed FSI methodology can be implemented in future follow-up studies involving groups of patients. The main findings revealed: a) counter-rotating vortices in the anastomosis cross-section affecting local pressure conditions; b) different temporal progression of vorticity, shear strain rate, and turbulent kinetic energy and similarity of the temporal progression of WSS obtained under the assumptions of the rigid-walled and FSI; c) a negligible low-WSS zone in the presented thrombosis-free AVF; d) migration of the zone of maximal temporal wall deformation over time.