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It is herein considered a new product composed of solid–liquid dispersion of a conveniently formulated continuous casting powder in synthetic oil‐based esters, where hypothetical limit to consider this liquid slurry as a liquid powder is a mix with at least 50% in weight powder load preserving suitable fluidity for effective and stable pumping. After a relatively long and intense industrial application period, one of most critical points when using liquid powder for steel continuous casting proves to be mold feeding. This is mainly because of weird properties of such material which behaves as a non‐Newtonian fluid. A thorough rheological study on samples of liquid powder for continuous casting is carried out. Based on meticulous characterization of a set of laboratory samples, the dispersion flow curve is determined. Most commonly used rheological models are then tested for fitting with the experimental data. Sisko model is identified as the best fitting one. This model is then implemented to derive the system curve describing its behavior under its industrial application conditions. The mathematical process to apply Sisko model and its numerical solutions is explained. The results found are consistent with the field experience of the industrial application of the material under study. [ABSTRACT FROM AUTHOR]

Smoking and hypertension are significant risk factors for atherosclerotic carotid artery disease, but also for intracranial aneurysms. The medical results suggest incidental intracranial aneurysms in patients with internal carotid artery (ICA) stenosis arteries. Which led to a study of the comparison between stenosis and aneurysm segments through the artery. A mathematical and numerical model for blood solidification and its rupture in a diseased artery is described in this paper. The interaction between the blood flow and a diseased arterial wall was formulated. The blood flow is formulated as a micropolar incompressible fluid with heat and mass transfer under the control of electro-osmotic and electromagnetic forces through an artery that contains stenosis and aneurysms. The approximation of mild stenosis is used to derive the governing flow equation, which is then solved using a method of finite difference. Particular attention is paid to the impact on axial velocity, flow rate, resistance impedance, and wall shear stress of geometrical parameters of the arterial wall and rheological blood parameters. In the instantaneous pattern of streamlines, the global behavior of blood is also investigated. Finally, the effect of all parameters on the blood flow through artery whose stenosis and aneurysm are investigated as a comparison of both segments. [ABSTRACT FROM AUTHOR]

Exudate and its viscosity are critical in wound healing. Changes in viscosity can interfere with dressings properties as well as affect the diffusion of immune cells, nutrients, oxygen and bacteria. Current international standards for laboratory testing of wound dressings use a single low‐viscosity solution, named as 'Test Solution A', which fails to simulate the diverse range of exudates encountered clinically. This study employs rheological analysis to characterise exudates viscosity, comparing cattle‐derived samples to the test solution A. Results reveal non‐Newtonian, shear‐thinning behaviour in exudates, contrasting with the Newtonian behaviour of the test solution A. Although clinically classified as 'seropurulent', three exudate samples analysed at 37°C present with different viscosity at various shear rates, ranging from 30.8 (±14.7) to 6.5 (±1.9) mPas. Findings show that the current tests on dressings employing Test Solution A are missing the complexity of real exudates. [ABSTRACT FROM AUTHOR]

There is a prevailing consensus that most Computational Fluid Dynamics (CFD) frameworks can accurately predict global variables under laminar flow conditions within the Food and Drug Administration (FDA) benchmark nozzle geometry. However, variations in derived variables, such as strain rate and vorticity, may arise due to differences in numerical solvers and gradient evaluation methods, which can subsequently impact predictions related to blood damage and non-Newtonian flow behavior. To examine this, flow symmetry indices, vortex characteristics, and blood damage—were assessed using Newtonian and four non-Newtonian viscosity models with CFD codes Ansys Fluent and OpenFOAM on identical meshes. At Reynolds number (Re) 500, symmetry breakdown and complex vortex shapes were predicted with some non-Newtonian models in both OpenFOAM and Ansys Fluent, whereas these phenomena were not observed with the Newtonian model. This contradicted the expectation that employing a non-Newtonian model would delay the onset of turbulence. Similarly, at Re 2000, symmetry breakdown occurred sooner (following the sudden expansion section) with the non-Newtonian models in both Ansys Fluent and OpenFOAM. Vortex identification based on the Q-criterion resulted in distinctly different vortex shapes in Ansys Fluent and OpenFOAM. Blood damage assessments showed greater prediction variations among the non-Newtonian models at lower Reynolds numbers. [ABSTRACT FROM AUTHOR]

In present research, an experimental and numerical study investigated for heat transfer of non-Newtonian nanofluid flows in corrugated tubes under constant heat flux which are equipped with twisted tapes. The experimental results are based on different Reynolds number from 2400 up to 6800 and with various volume concentrations of silicon dioxide nanoparticles and different twisted ratios. Present numerical simulation is carried out by utilizing computation fluid dynamic (CFD) code and for validation of obtained results, they are compared to various turbulence modeling and empirical correlations presented by other researchers. Results of experiments showed that amount of power law index of non-Newtonian nanofluids increased while the consistency index generally decreased by intensifying volume concentrations of nanoparticles. Moreover, the numerical results showed standard κ–ε model of turbulence is more proper model rather than other available models. [ABSTRACT FROM AUTHOR]

The use of nanoparticles in heat transmission is an interesting research subject and many scholars have shown an interest in this topic. In accordance with the motivating relevance of nanomaterials, the current research advocates for an evaluation of Casson nanofluid using porous medium thermal analysis in conjunction with vibrant implementations of mixed convection through a chemical reaction. Additionally, a nonlinear suction/injection phenomenon is taken into consideration. A consistent flow pattern is created by the stretched porous structure. The extended Casson nanofluid model is used to identify the heat production of non-Newtonian fluids. The essential incentives for choosing the Casson nanofluid model are validated as it simultaneously achieves Casson fluid, nanofluid and porous medium outcomes. The convective transport of nanofluid has been addressed using convective temperature boundary conditions and convective flow. A dimensionless form with similarity variables is used to simplify the fundamental equations for the provided flow model. The fourth-order Runge–Kutta (RK) strategy is deployed to arrive at a numerical solution for simulated flow. The physical conveyance of flow variables is accessed visually. It is calculated from engineering quantities (i.e., skin friction, Nusselt number and Sherwood number) to generate the numerical values. The velocity declines with increasing porosity and material factors while opposite outcomes are witnessed for buoyancy factors (mixed convection and buoyancy ratio) and injection factor. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the existence of a finite stopping time for solutions in the form of variational inequality to fluid flows following a power law (or Ostwald–DeWaele law) in dimension N ∈ { 2 , 3 } . We first establish the existence of solutions for generalized Newtonian flows, valid for viscous stress tensors associated with the usual laws such as Ostwald–DeWaele, Carreau–Yasuda, Herschel–Bulkley and Bingham, but also for cases where the viscosity coefficient satisfies a more atypical (logarithmic) form. To demonstrate the existence of such solutions, we proceed by applying a nonlinear Galerkin method with a double regularization on the viscosity coefficient. We then establish the existence of a finite stopping time for threshold fluids or shear-thinning power-law fluids, i.e. formally such that the viscous stress tensor is represented by a p-Laplacian for the symmetrized gradient for p ∈ [ 1 , 2) . [ABSTRACT FROM AUTHOR]

A modified paddle mixer suitable for the homogenization of viscoplastic fluids and pastes, such as contemporary concrete mixtures, was developed to enhance homogeneity of the product, a crucial step in ensuring desired mechanical properties. In addition to the improvement in flow characteristics, this study presents the basic dimensionless characteristics in regression form, along with the measurement of the Metzner–Otto constant. These characteristics are essential for the use of the paddle mixer as an onsite rheometer, enabling rapid and straightforward evaluation of the desired rheological properties of the prepared mixture. The performance of the paddle mixer was assessed through homogenization experiments and power input measurements at various rotation speeds. The paddle mixer displayed creeping flow behavior up to a Re value of 50. The geometry of the paddle mixer was modified to achieve homogeneity throughout the volume, significantly influencing mixing mainly in the axial region of the mixer. To compensate for the non-Newtonian behavior, the Metzner–Otto approach was employed. Under creeping flow conditions and for pastes displaying flow index above 0.5, the paddle mixer can be characterized by a Metzner-Otto constant of 54.

AbstractThis article presents a numerical investigation and analysis of the cooling effectiveness of thermomagnetic transient natural convection in a long channel, equipped with four cylindrical heat-generating blocks. A non-Newtonian power-law ferrofluid was employed for the present investigation to achieve optimum cooling. The governing equations are the continuity equation, the momentum equation and the energy equation. The finite volume method was used to solve the resulting algebraic system. From an energy-saving point of view, this configuration can provide a good approximation for selecting effective physical and geometrical parameters to design a reliable thermal system. For this purpose, the study was carried out for various geometric and thermophysical parameters. Different values of thermal conductivity, power law index, Rayleigh number, Hartmann number and ferrofluid volume fraction, were considered. The results are illustrated in the form of streamlines, isotherms, average Nusselt and a spatio-temporal characterization of the mean ferrofluid velocity. From the results presented, we can conclude that the choice of non-Newtonian, pseudoplastic ferrofluid with a low thermal conductivity ratio subjected to a uniform magnetic field proves to be a crucial solution for efficient and stable cooling of heat-generating cylindrical blocks, which will have to be close to the cold walls of the channel. [ABSTRACT FROM AUTHOR]

The growing need for industrial development, limited availability of non-renewable energy resources, minimizing energy consumption, and ecosystem concerns has prompted researchers to explore the practical applications of two-phase nanofluid materials processing and electromagnetic energy emitted via the sun. Therefore, using two-phase nanofluids in solar thermal technology systems can enhance system performance by improving heat absorption and transfer efficiency. Owing to its usage, this study examines the magnetized two-phase nanofluid flow on a two-dimensional laminar mixed convective boundary layer with the impact of multiple slips. The flow contains an electrically conducting non-Newtonian nanofluid over a deformable (stretching/shrinking) sheet with a solar radiation effect. Also, the study utilizes a nonlinear Roseland diffusion flux approximation to incorporate the solar radiation effect, which is valid for nanofluid media with high optical density. This work utilizes similarity variables to simplify the partial derivative model into ordinary differential equations. These equations are then solved using the wavelets and Chebyshev wavelets scheme with the help of MATHEMATICA 11.3 software. According to the findings, the nanoparticle volume fraction is increased for high electrical conductivity (M = 2) and decreased for the electrically non-conducting case (M = 0). [ABSTRACT FROM AUTHOR]

In this article, we discuss the bioinspired peristaltic pumping mechanism of an elastic non-Newtonian fluid whose rheology is characterized by the Phan-Thien-Tanner model in a microfluidic configuration. We consider the effect of an electroosmotic body force originating from electrical double layer phenomena formed in the wall of the fluidic channel of finite length. The considered configuration is consistent with the natural contraction of the oesophagus wall that does not involve expansion beyond the stationary boundary. Employing lubrication theory and assuming the underlying flow to be in the creeping flow regime, we outline the transport equations pertaining to the chosen peristaltic set up. The transport equations are then solved using a well-established method consistent with perturbation technique. By depicting the pressure variation and wall shear stress graphically for a continuous wave train, we aptly discuss the time-averaged net throughput and flow developed at channel inlet of the chosen pathway and demonstrate the eventual consequences of these flow patterns for a window of viscoelastic and electrokinetic parameters. The outcomes obtained from this model establishes that the underlying flow owing to the peristaltic pumping mechanism strongly relies on the rheological parameter ε W e 2 . These inferences are expected to be of extensive importance in designing peristalsis pump, mimicking features of the physiological system, for achieving unidirectional flow of complex fluids with improved efficiency, frequently used in biochemical/biomicrofluidic applications. [ABSTRACT FROM AUTHOR]

In recent years, the examination of blood flow in diseased arteries has been an essential field of research. Atherosclerosis is one of the most common arterial diseases, usually known as stenosis. The current work investigates the combination impact of electric and magnetic fields of the unsteady, two-dimensional and laminar pulsatile non-Newtonian flow of blood in an axisymmetrically inclined tapered porous stenotic artery containing gold nanoparticles with different shapes subject to body acceleration and slip effect at the wall. Heat source and thermal radiation are also considered. The phenomenon of the imposed electric field is described by the Poisson–Boltzmann equation. To immobilize the effect of the vessel wall, a transformation of the radial coordinates is used. The adoption of gold nanoparticles as nanomaterials for drug delivery is mainly due to their stability, inert nature, absence of cytotoxicity, high disparity and biocompatibility. An explicit scheme of finite differences is employed for solving the nonlinear partial differential equations that govern the current problem, as well as the prescribed boundary conditions. The applied magnetic and electric fields have significant effects on the flow field and heat transfer. [ABSTRACT FROM AUTHOR]

The steady rheological behavior of suspensions of solid particles thickened by cellulose nanocrystals is investigated. Two different types and sizes of particles are used in the preparation of suspensions, namely, TG hollow spheres of 69 µm in Sauter mean diameter and solospheres S-32 of 14 µm in Sauter mean diameter. The nanocrystal concentration varies from 0 to 3.5 wt% and the particle concentration varies from 0 to 57.2 vol%. The influence of salt (NaCl) concentration and pH on the rheology of suspensions is also investigated. The suspensions generally exhibit shear-thinning behavior. The degree of shear-thinning is stronger in suspensions of smaller size particles. The experimental viscosity data are adequately described by a power-law model. The variations in power-law parameters (consistency index and flow behavior index) under different conditions are determined and discussed in detail. [ABSTRACT FROM AUTHOR]

Hybrid nanofluids are making waves in industry because of their superior thermal efficiency and innovative designs. Their usefulness extends to many other sectors and domains of study. The volume fraction of Cu--Al2O3 and Ag--TiO2 hybrid nanoparticles in nanofluids will be studied to determine their impact on heat transmission and flow. The study also considers the presence of heat radiation, a magnetic field, and other relevant factors. The non-Newtonian Reiner-Philippoff model was employed to investigate the flow's shear thickening and thinning properties. The combined effects of suction and a contracting surface form a boundary for the surface. The reduced partial differential equation (PDE) is solved using the MATLAB tool bvp4c following the similarity transformation method. The shrinking sheet shows that the dual solution converges to critical points, and the stability study verified that the first one is stable and physically trustworthy. The mathematical modelling developed for nanofluid hybrids has exhibited a significant impact on the overall heat flow, which can be attributed to the variation in the parameters that influence it. Enhancement in magnetic parameter (+2.26%), suction (+2.99%), and nanoparticle fractional volume of metal oxide (+0.4%) were identified as factors that accelerated heat transfer to the pioneering Cu--Al2O3 nanofluid hybrid, according to the study. Besides, the second hybrid of Ag--TiO2 nanofluids had a reduced heat transfer rate due to changes in thermal radiation (-2.14%) and Reiner parameter-Philippoff fluid (-0.14%). [ABSTRACT FROM AUTHOR]

Despite the ubiquity and prevalence of rheological consistency across a wide range of industries, there is no clear consensus on its meaning or on one particular technique for quantifying it. Instead, there exist various definitions of "consistency" that are each specific to a given context, and each industry has its own procedure for measuring it. This paper organizes the many subjects and terminologies associated with consistency, providing a comprehensive guide of fundamental mechanics, fundamental properties, modeling techniques, and standardized tests that describe consistency. This includes outlining the rheological models that describe the behavior of viscoelastic and non-Newtonian materials as well as the identification of numerous parameters that can be individually evaluated to comprehensively understand and quantify consistency. Such an understanding of consistency and its underlying mechanical properties encourages the refinement of current consistency test methods and development of new ones. [ABSTRACT FROM AUTHOR]

With the availability of efficient and sophisticated finite element analysis (FEA) and computational fluid dynamics (CFD) tools, engineering designs are becoming more software-driven and simulation-based. However, the insights relevant to engineering designs tend to be hidden within massive temporal and spatial data produced with full-fledged three-dimensional simulations. In this paper, we present a preliminary study of the controlled intermittent dispensing of a typical non-Newtonian glue employed in the manufacturing of electric vehicles (EVs). The focus of the study is on the scaling issues derived from different computational and analytical models of interest and importance to the precision control of this non-Newtonian fluid, the lowest dynamic viscosity of which at extremely high shear rates is nearly four million times that of water. More specifically, the abrupt change of the inlet pressure with a constant outlet or ambient pressure and various modeling strategies for transient viscous internal flow with both Newtonian and non-Newtonian fluids are modeled and compared. The analytical and computational results of the developing Newtonian fluid, i.e., water, are derived and computed for validation and verification purposes before the actual applications to the developing non-Newtonian fluid. The concept of a well-established relaxation time before the onset of the steady solution for Newtonian fluids has been validated with both analytical and computational approaches before its expansion and adoption to non-Newtonian fluids with complex rheological behaviors. Other issues attributed to transient operations and precision controls of non-Newtonian fluid delivery involve the pressure pulse and pressure wave propagation within the flexible pipe with compressible or almost incompressible non-Newtonian fluids with a constant pressure at the outlet and a constant mass flow rate or average axial velocity at the inlet, which will be addressed in a separate paper. [ABSTRACT FROM AUTHOR]

Food rheology is key to manage the swallowing safety of people affected by swallowing disorders (dysphagia). Simple approaches to assess the flow properties of texture-modified drinks are widely used, but relatively poorly understood. This study focuses on the International Dysphagia Diet Standardisation Initiative (IDDSI) flow test, adopted by caregivers worldwide. This test considers the gravity-driven flow in a vertical syringe. Newtonian liquids and non-Newtonian fluids obtained using a commercial starch-based thickener were considered in this study. An accurate theoretical description of the flow is proposed for Newtonian and power-law fluids considering the effect of fluid properties and of the syringe geometry. A rheological map is proposed, based on the results of several thousand simulations, to capture quantitatively the effect of rheological properties and density on the IDDSI classification, highlighting the important effect of the fluid density which is usually ignored. The sensitivity of the IDDSI results with respect to the syringe outlet diameter is discussed, as well as the different average shear rates at which different IDDSI levels are tested. The rheological map also shows quantitatively that different combinations of the fluid rheological properties and density can result in the same IDDSI classification, suggesting interesting directions for future clinical research. [ABSTRACT FROM AUTHOR]

A computational fluid dynamics coupled population balance model (CFD-PBM) was used to numerically simulate the fluid dynamics of bubble swarms in a bubble column containing non-Newtonian fluids. The effects of superficial gas velocity (Ug), the consistency index (K), and the flow index (n) on bubble size distribution (BSD), gas holdup, and fluid dynamic viscosity in a bubble column were analyzed at both local and overall scales. As Ug increases, the bubble breakup occurs excessively, the gas holdup increases, and the dynamic viscosity decreases. K and n were used to characterize the rheological properties of power law fluid. As K increases, fluid viscosity increases, bubble breakup rate decreases, gas holdup in the top zone is slightly lower than in the middle zone, and dynamic viscosity increases. Within the range of n from 0.45 to 1.07, when n is smallest, the relative frequency of bubbles smaller than the initial size is relatively large, and the overall and local gas holdup are the highest. When n = 1.07, the fluid exhibits shear-thickening properties, and the dynamic viscosity variations are significant. [ABSTRACT FROM AUTHOR]

Bifurcated vessels represent a typical vascular unit of the cardiovascular system. In this study, the blood flow in symmetric and asymmetric bifurcated vessels are simulated based on computational fluid dynamics method. The blood is modeled as non-Newtonian fluid, and the pulsatile flow velocity is applied on the inlet. The effects of the fluid model, bifurcation angle and symmetry of the geometry of the vessel are investigated. The results show that the wall shear stress (WSS) on the outer wall of daughter branches for the non-Newtonian fluid flow is greater than that for Newtonian fluid flow, and the discrepancy between the flow of two fluid models is obvious at relatively low flow rates. With the bifurcation angle increases, the peak axial velocity of the cross-section of daughter branch decreases, so the WSS increases. For the non-Newtonian fluid flow in the asymmetric bifurcated vessels, more flow passes through the daughter vessel with a lower angle, and the WSS along the outer wall of which is lower. Furthermore, the region with a low time-averaged wall stress (TAWSS) and high oscillating shear index(OSI) distributed on the outer wall of bifurcation vessels are larger for the flow in the vessel with smaller bifurcation angle. In conclusion, the effects of the blood viscosity cannot be neglected at low flow rates and the geometry of the bifurcated vessel plays a key role with regards to the blood flow. [ABSTRACT FROM AUTHOR]

Magnetic drug targeting (MDT) has garnered significant attention in the field of cancer treatment and other diseases due to its ability to minimize side effects and enhance treatment efficacy. This approach involves the injection of magnetic nanoparticles into the bloodstream, which are then guided to the tumor site through the application of an external magnetic field. In this particular study, the researchers focused on investigating the impact of various factors on the absorption of nanoparticles downstream of a stenosis in a vessel with local symmetric stenosis. Specifically, they examined the effects of the nanoparticles' diameter, Reynolds number, the Newtonian and non-Newtonian behavior of blood, magnetic field strength, and the type of magnetic field source. The two types of magnetic field sources considered were a current-carrying wire and a permanent magnet. The findings revealed that an increase in the nanoparticles' diameter and the magnetic field's strength led to an increase in the number of captured nanoparticles. Conversely, an increase in the Reynolds number resulted in a decrease in the captured nanoparticles. Additionally, the study highlighted the importance of considering blood as a non-Newtonian fluid for blood velocities lower than 60 mm/s (i.e., in arteries with a diameter lower than 2 mm). Furthermore, when comparing the efficiency of different magnetic fields, it was observed that the current-carrying wire was more effective for small-sized vessels with stenosis. [ABSTRACT FROM AUTHOR]

The free convection of a non-Newtonian fluid in an equilateral triangular cavity containing a triangle obstruction in various positions is investigated numerically in this paper. The research is carried out using the finite element method. The sloped side walls are adiabatic, while the bottom is kept heated. At the obstacle, three positions are examined. The effects of different power law indexes on free convection have been investigated. The temperature field, fluid flow, and heat transfer are all highly influenced by the obstacle's location, Rayleigh number, and power law index. The resulting outcomes are confirmed using existing results in the literature and verified using a grid sensitivity analysis. A comparison of the current results to those found in the literature demonstrates the study's dependability and trustworthiness.

Bifurcated vessels represent a typical vascular unit of the cardiovascular system. In this study, the blood flow in symmetric and asymmetric bifurcated vessels are simulated based on computational fluid dynamics method. The blood is modeled as non-Newtonian fluid, and the pulsatile flow velocity is applied on the inlet. The effects of the fluid model, bifurcation angle and symmetry of the geometry of the vessel are investigated. The results show that the wall shear stress (WSS) on the outer wall of daughter branches for the non-Newtonian fluid flow is greater than that for Newtonian fluid flow, and the discrepancy between the flow of two fluid models is obvious at relatively low flow rates. With the bifurcation angle increases, the peak axial velocity of the cross-section of daughter branch decreases, so the WSS increases. For the non-Newtonian fluid flow in the asymmetric bifurcated vessels, more flow passes through the daughter vessel with a lower angle, and the WSS along the outer wall of which is lower. Furthermore, the region with a low time-averaged wall stress (TAWSS) and high oscillating shear index(OSI) distributed on the outer wall of bifurcation vessels are larger for the flow in the vessel with smaller bifurcation angle. In conclusion, the effects of the blood viscosity cannot be neglected at low flow rates and the geometry of the bifurcated vessel plays a key role with regards to the blood flow.

AbstractThis study explores the impact of ternary hybrid nanofluid and velocity slip on the Non-Newtonian fluid flow between two nonparallel plates. Additional influence of an applied magnetic field is considered with Casson fluid (Blood) as a base fluid. Both analytic and numerical techniques are employed to comprehensively analyze the system’s behavior under these combined effects. The governing partial differential equations (PDEs) governing continuity and momentum are simplified into a system of ordinary differential equations (ODEs) through similarity transformations. To obtain an explicit series solution for the resulting problem, we employ the Duan Rach approach (DRA). Subsequently, we conduct a thorough analysis of the solution’s convergence to ensure its reliability and accuracy. The same problem is also solved by using the Runge-Kutta-Fehlberg 4th–5th order approach featuring shooting technique and an excellent agreement is observed between the two sets of results. A comparison was made between the results obtained from this investigation in particular cases and the results obtained via the HAM-based Mathematica package for validation. Influence of various parameters of practical importance on the velocity and temperature profiles is studied and portrayed graphically. Values of skin friction coefficient are tabulated by assigning different values to various emerging parameters. It is found that the velocity slip parameter has a positive value in a converging channel, it implies that there is a slip between the fluid and the channel wall, and the slip velocity is directed in the same direction as the flow. Hence velocity increases. Also, results obtained reveal that for positive value of β+ velocity gets high in converging case and lower velocity can be seen in diverging geometry. Same behavior is seen for β−. [ABSTRACT FROM AUTHOR]

Cardiovascular illnesses are a primary global health concern because they are frequently brought on by arterial stenosis. The complicated hemodynamics of blood flow via elliptically shaped arteries with numerous stenotic lesions along their top and bottom walls are examined in this paper. Carreau fluid model is used with Navier–Stokes equations in this study. The complete comparative study is done by using the Finite Element and Finite Volume Methods. This study uses commercial software to examine blood flow velocity, pressure and temperature distributions under various physiological situations at Reynolds number 30. Our results illuminate the interaction between flow dynamics, stenosis characteristics, and arterial geometry. The novelty of the work is to investigate how stenosis size, shape, and location affect pressure gradients, and flow disturbances. These observations provide helpful direction for understanding disease progression, designing treatments, and possibly new stent designs. The future direction of this research may involve further exploration of the interplay between hemodynamics and arterial stenosis by incorporating advanced computational models. Additionally, studies focusing on in vivo validation and clinical applications could enhance the translational impact of the findings. Collaborations between researchers, clinicians, and engineers may pave the way for personalized treatment strategies and innovations in cardiovascular care based on a deeper understanding of the intricate dynamics within diseased arteries. [ABSTRACT FROM AUTHOR]

In this paper, inscribed non-Newtonian Williamson fluid relaxation and contraction phenomena due to the effect of magnetohydrodynamics (MHD) is taken into account. This issue is modeled, and precise solutions are handled using a low Reynolds number and long wavelength approximation. Graphical depiction of the consequences of various parameters on temperature and velocity are provided. It becomes clear that the temperature reactions to increases in Biot numbers are decreased. Considering a cylindrical coordinate system, the impact of various physical parameters on the temperature distribution, velocity, the pressure gradient, and frictional force are secured from the flow for non-Newtonian Williamson fluid exposed from MATLAB. Additionally, it has been discovered that the velocity profile at the tube's center increases for shear-thinning a fluid and decreases for thickening a fluid. Furthermore, the peristaltic walls show the opposite behavior. [ABSTRACT FROM AUTHOR]

A modified paddle mixer suitable for the homogenization of viscoplastic fluids and pastes, such as contemporary concrete mixtures, was developed to enhance homogeneity of the product, a crucial step in ensuring desired mechanical properties. In addition to the improvement in flow characteristics, this study presents the basic dimensionless characteristics in regression form, along with the measurement of the Metzner-Otto constant. These characteristics are essential for the use of the paddle mixer as an onsite rheometer, enabling rapid and straightforward evaluation of the desired rheological properties of the prepared mixture. The performance of the paddle mixer was assessed through homogenization experiments and power input measurements at various rotation speeds. The paddle mixer displayed creeping flow behavior up to a Re value of 50. The geometry of the paddle mixer was modified to achieve homogeneity throughout the volume, significantly influencing mixing mainly in the axial region of the mixer. To compensate for the non-Newtonian behavior, the Metzner-Otto approach was employed. Under creeping flow conditions and for pastes displaying flow index above 0.5, the paddle mixer can be characterized by a Metzner-Otto constant of 54. [ABSTRACT FROM AUTHOR]

We investigate the local-in-time existence results of classical solutions to the 3D (Hall-)MHD equations with power-law type nonlinear viscous fluid when magnetic resistance is vanished and also show the global-in-time existence of classical solutions under small initial data. Moreover, we prove the space-time decay property for these solutions. [ABSTRACT FROM AUTHOR]

This study investigates the mixing of non-Newtonian fluids in microfluidic devices using electrokinetic phenomena Micromixing is a crucial operation that finds multiple applications in chemical research and biomedical diagnostics. In order to improve mixing, multiple combinations of heterogeneously charged triangular elements are considered for investigation. The power-law model was used to characterize the non-Newtonian behavior of fluids. The effect of different geometrical parameters (hurdle length, height, number, and shape) and electrical parameters (applied external electric field and zeta potential on hurdles) on mixing are evaluated. The results indicate that the element shape, number, and fluid viscosity significantly affect mixing in microchannels. Moreover, the homogeneity of the mixed fluids increases with the flow behavior index (n). We found that dilatant fluids mix relatively better than pseudoplastic fluids. Finally, the Taguchi technique used to evaluate the combined effect of all factors and obtained optimal mixing conditions for various flow behavior indices (n) of non-Newtonian fluids. [ABSTRACT FROM AUTHOR]

Abstract\nCULMINATIONSThe ureter typically experiences a frequency of one to five peristaltic contractions per minute. However, it is important to note that these contractions can be disrupted by various physical and mechanical irritants. Ionic contents in the urine make it electrically conducting and responsive to electromagnetic body forces. MHD can be deployed in bio magnetic therapy to control or mitigate symptoms associated with peristaltic pumping in the urinary system.  This article therefore focuses on the hydromagnetic effects on flow patterns of urine with debris (monoliths). The mechanism of urine flow is largely coordinated by the kidneys. The flow inside the ureter is interrupted by microliths, which are generated by the sedimentation of excretory products. To simulate this, a two-phase formulation is adopted, comprising the electromagnetic urological viscous fluid phase and the particulate phase for solid grains. The peristaltic propulsion of two-phase liquid in the ureter is simulated as a sinusoidal wave propagation of incompressible non-Newtonian fluid. The Williamson viscoelastic model is deployed for the rheology. Heat transfer is also included with Soret thermo-diffusion and viscous heating effects. Long wave and low Reynolds number approximations are employed based on lubrication theory. The mass, momentum, energy and concentration conservation equations with associated boundary conditions are rendered non-dimensional via appropriate scaling transformations. A numerical solution is achieved via BVP4C MATLAB quadrature.  Graphical visualizations of the velocity, temperature and concentration (solid grains) are given for the influence of suspension parameter (ζ), Hartmann number (M), Prandtl number (Pr), Weissenburg number (We), particle volume fraction (C), Eckert number (Ec), Soret number (Sr), Schmidt number (Sc). The novelty of the present work is therefore the simultaneous consideration of a generalized two-phase model, wall slip, non-Newtonian characteristics, cross diffusion, viscous dissipation, mass diffusion, magnetic body force and curvature effects in peristaltic urological transport, which has not been undertaken previously. The detailed simulations reveal that the flow velocity is reduced due to the presence of solid particles and the channel curvature, in comparison to the flow in an unobstructed channel devoid of solid particles. Enhancing the hydrodynamic slip parameter speeds up the movement of particles and fluid near the channel walls, boosts wall skin friction, raises pressure difference in the pumping area, and amplifies bolus magnitudes.The rise in peristaltic pumping results in a reduction in solid particle concentration, which is significant phenomena.This theoretical approach may aid in treating conditions such as Urinary Tract Infections (UTIs). The computations effectively demonstrate that significant manipulation of urological pumping characteristics can be achieved with an electromagnetic field. Some new features of two-phase ureteral dynamics are highlighted as relevant to magnetic therapy techniques, which may be beneficial to clinicians.A detailed new formulation is given for magnetohydrodynamic (MHD) two-phase Williamson non-Newtonian ureteral transport with mass diffusion, Soret cross diffusion, viscous heating and peristaltic wave propulsion.We compute numerically the pressure gradient, skin friction, Nusselt number, and wall shear stress in a planar channel with flexible walls, which serves as a model for the ureter under a transverse magnetic field.We also investigate the impact of Hartmann number and Weissenberg non-Newtonian number on fluid and particle phase velocities.The present work reveals some interesting insights into electromagnetic ureteral peristaltic multi-phase non-Newtonian thermo-solutal transport phenomena via extensive visualization.There is a strong suppression in the ureteral fluid phase velocity for greater magnetic field confirming the excellent flow control abilities of Magnetic Ureteral Therapy (MUT).A detailed new formulation is given for magnetohydrodynamic (MHD) two-phase Williamson non-Newtonian ureteral transport with mass diffusion, Soret cross diffusion, viscous heating and peristaltic wave propulsion.We compute numerically the pressure gradient, skin friction, Nusselt number, and wall shear stress in a planar channel with flexible walls, which serves as a model for the ureter under a transverse magnetic field.We also investigate the impact of Hartmann number and Weissenberg non-Newtonian number on fluid and particle phase velocities.The present work reveals some interesting insights into electromagnetic ureteral peristaltic multi-phase non-Newtonian thermo-solutal transport phenomena via extensive visualization.There is a strong suppression in the ureteral fluid phase velocity for greater magnetic field confirming the excellent flow control abilities of Magnetic Ureteral Therapy (MUT). [ABSTRACT FROM AUTHOR]

The migration of sperm cells in a female reproductive tract is responsible for the successful fertilization of the female egg. In this research work, the effect of the surrounding fluids on the motion of sperm cells has been studied using a microfluidic channel. To analyze the motility of sperm, primary motility parameters such as velocity, beat frequency, amplitude, and derived parameters such as linearity, straightness, and wobble have been measured. The results indicate that sperms possess higher progressive motility in non-Newtonian fluids compared to Newtonian fluids in the same viscosity range. The motion of the sperm shows an inverse relationship between the amplitude of the head trajectory and the beat frequency of the flagella. Numerical studies were performed to measure the drag force on these sperm. The trajectories of the flagella, forces acting on sperm, power generated, pulling power, and efficiency of the sperm motion through the fluid medium have been investigated and a relationship between the force and rotation of the flagella has been established. The results show that the flagella also change their shape based on the properties of the surrounding fluid. This study aims to improve our understanding of issues related to infertility diagnosis and help design in-vitro experiments required for sperm separation. [ABSTRACT FROM AUTHOR]

Introduction: Flow dynamics due to the peristaltic pumping has been the topic of great interest for the researchers. But numerical and analytical analyses for the peristaltic motion are limited where flow domain is deformed real-time. Research on peristalsis has a limitation where theoretical aspects of walls motion are considered, neglecting the real time deformation of the walls.Objectives: This paper aims to propose a more reliable and accurate numerical methodology for peristaltic motions to address the above-mentioned challenge. Stream traces, velocities, and pressure drops along the tube is to be visualized more accurately.Methods: In present study a finite volume based dynamic mesh motion method is adopted to analyze the peristaltic motion of a non-Newtonian Quemada fluid in an axisymmetric channel. The walls and interior domain of the channel is dynamically deformed for a sinusoidal wave traveling on boundary.Results: Simulation of unsteady flow behavior for time t=0s to 2s and amplitude ratio Φ=0.2,0.4,and0.6. predicts fluid trapping phenomenon. Rotation of fluid particles is more prominent for higher amplitude ratios. Pressure gradient increases with increasing amplitude ratios.Conclusion: A novel dynamic mesh method is proposed for peristaltic pumping. It provides more accurate and more physical results for stream traces; pressure drops and velocities along the tube. A limited case of the study validates the theoretical and analytical results already presented in literature; hence the method is reliable.

There is a prevailing consensus that most Computational Fluid Dynamics (CFD) frameworks can accurately predict global variables under laminar flow conditions within the Food and Drug Administration (FDA) benchmark nozzle geometry. However, variations in derived variables, such as strain rate and vorticity, may arise due to differences in numerical solvers and gradient evaluation methods, which can subsequently impact predictions related to blood damage and non-Newtonian flow behavior. To examine this, flow symmetry indices, vortex characteristics, and blood damage—were assessed using Newtonian and four non-Newtonian viscosity models with CFD codes Ansys Fluent and OpenFOAM on identical meshes. At Reynolds number (Re) 500, symmetry breakdown and complex vortex shapes were predicted with some non-Newtonian models in both OpenFOAM and Ansys Fluent, whereas these phenomena were not observed with the Newtonian model. This contradicted the expectation that employing a non-Newtonian model would delay the onset of turbulence. Similarly, at Re 2000, symmetry breakdown occurred sooner (following the sudden expansion section) with the non-Newtonian models in both Ansys Fluent and OpenFOAM. Vortex identification based on the Q-criterion resulted in distinctly different vortex shapes in Ansys Fluent and OpenFOAM. Blood damage assessments showed greater prediction variations among the non-Newtonian models at lower Reynolds numbers.

AbstractResearch on blood flow in diseased arteries has become a priority in recent years. Stenosis/aneurysm is the most common arterial diseases. This work investigates the mixed effect of electric and magnetic fields on the unsteady, two-dimensional, laminar, non-Newtonian pulsatile flow of blood in an axisymmetrically inclined tapered porous artery with stenosis and aneurysm containing gold nanoparticles, subjected to body acceleration and slip effect. Thermal radiation and heat sources are also included. To immobilize the effect of the vessel wall, we use a radial coordinate transformation. The nonlinear partial differential equations governing the present problem, together with the prescribed boundary conditions, are solved using an explicit finite-difference scheme. The current analysis could help to understand the improvement in mass distribution and heat transfer in diseased blood vessels, which might be useful for drug delivery in the therapy of stenosis and aneurysm. [ABSTRACT FROM AUTHOR]

Introducing swirling velocity at the inlet is one of the best ways to enhance the transport properties of flow through the pipes. Flow of fluids in small tubes have important applications involving fluid mixing or heat transfer and the flow in these small devices appears to be laminar in nature. Non-Newtonian fluids have wide variety of applications in small pipes ranging from heat-pipes to micro heat exchangers. Hence, it becomes very important to enhance the transport properties of fluids flowing through small devices. To enhance the transport characteristics, the method of introducing swirling of fluid at the inlet of the pipe is chosen. Further, the effect of important dimensionless parameters such as the power-law index of the fluid (characterizes fluid rheology), Reynolds number, the inlet swirl velocity profile shape (transition radius) and the inlet swirl number on the heat transfer characteristics is investigated. The qualitative and quantitative aspects of the heat transfer problem are discussed with particular focus on temperature contours and determination of Nusselt number. Results from the present study show that the power-law index of the fluid and Reynolds number plays an important role in enhancing the heat transfer. Increase in the flow Reynolds number and decrease in the power-law index tend to increase heat transfer strongly. It is also revealed that the inlet swirl number and the profile shape (transition radius) have a weak effect on the augmentation of heat transfer. A correlation is proposed to determine the heat transfer in the form of Nusselt number based on the flow Reynolds number and power-law index. [ABSTRACT FROM AUTHOR]

This study connects and compares the results from two different rheological measurement techniques, namely, the slump test and rotational rheometry, on UHPC (Ultra-High-Performance Concrete) through the use of commercially available numerical simulation software ANSYS Fluent 2022 R2. The workability and resulting mechanical properties of the UHPC (a material used in construction) are highly dependent on its rheology and, hence, also on the composition and level of homogeneity of the assessed mixture. It is generally understood that the most suitable rheological model for concrete mixtures is the Hershel–Bulkley model. However, obtaining reliable rheological data is complicated as the wide-gap rotational rheometers developed for concrete show bias in their measurements even on precise laboratory equipment, while common industrial tests, such as the slump test, do not produce the usual shear rate–shear stress relation and, hence, do not allow for more complex analysis. Recently, a new methodology for the rheological measurement of non-Newtonian fluids that utilises a simple power input–rotation speed measurement was published. However, in this study, only model liquids were evaluated, and the method was not validated for more complex fluids such as pastes. Therefore, it was the goal of this study to show this method's suitability for fine pastes through a comparison with the slump test, using numerical simulation. [ABSTRACT FROM AUTHOR]

The fully developed turbulent flow of pseudoplastic (n = 0:75) and Newtonian fluids in an isothermal axially rotating cylinder has been carried out using a large eddy simulation (LES) with an extended Smagorinsky model. The simulation Reynolds number of the present predictions has been assumed to be Res = 4000 at various rotation rates ð0 x N x 3Þ: This investigation seeks to assess the influence of the centrifugal force induced by the swirl on the mean flow quantities, turbulent statistics, and instantaneous turbulence structure to describe the rheological behavior and the turbulence features. The predicted results indicate that with increasing rotation rate, the pseudoplastic fluid tends to behave like a liquid when approaching the pipe center due to the lower apparent fluid viscosity in the logarithmic region as the pipe wall rotates. Moreover, the reduction in the pseudoplastic apparent viscosity in the core region induces a pronounced increase in the axial velocity profile further away from the pipe wall toward the core region. It is interesting to note that the growth of the centrifugal force induced by the swirl driven by the rotating pipe wall results in an apparent attenuation in turbulence intensities of the axial velocity fluctuation and, consequently, in the kinetic energy of turbulent fluctuations and the turbulent Reynolds shear stress of the axial-radial velocity fluctuations, as the pipe wall rotates. Moreover, the increased rotation rate leads also to a noticeable increase in the Root mean square (RMS) of the radial and tangential fluctuations. It can be said that the transport mechanism of turbulence intensities from the axial components to the other ones exhibits a marked increase with increasing pipe wall rotation. [ABSTRACT FROM AUTHOR]

Thermal treatments are essential to abate the microbial load in food matrices and ensure food safety. Heat exchangers (HEs) are commonly adopted for the pasteurization of liquid foods, thanks to their simple structure and ease of use. In particular, tubular HEs are often employed with viscous fluids and products containing fibres and pieces. The aim of pasteurization is to ensure that every point of the product reaches and maintains the target temperature for an adequate amount of time. To this end, it is essential to guarantee uniformity and prevent portions of fluid from reaching an insufficient temperature, and others from being overheated. To evaluate the thermal treatment inside a tube-in-tube HE, computational fluid dynamics (CFD) was used to simulate a pilot plant. Three different fluids with shear-thinning temperature-dependent non-Newtonian behaviour were evaluated. A CFD simulation campaign was carried out reproducing, for each juice, the thermal treatment under different operating conditions. Then, the results were analysed with statistical techniques to evaluate the impact of each operating parameter on the treatment, highlighting how high viscosity greatly impacts the thermal treatment, resulting in lower average temperature and temperature uniformity, while causing an increase in the pressure drop. The results of the simulation campaign were also used to generate a reduced order model (ROM) of the device, that could be exploited to estimate the outcomes of a treatment both as averaged values on a section or at a specific point like "virtual sensors". The ROM could be also adopted to design and evaluate alternative treatments by performing numerical optimization based on given objectives and constraints. Finally, as the ROM can be implemented in real-time, it could be used to monitor and control the functioning of food plants, detecting deviations from the expected conditions and possible failure conditions. [ABSTRACT FROM AUTHOR]

We find solutions that describe the levelling of a thin fluid film, comprising a non-Newtonian power-law fluid, that coats a substrate and evolves under the influence of surface tension. We consider the evolution from periodic and localized initial conditions as separate cases. The particular (similarity) solutions in each of these two cases exhibit the generic property that the profiles are weakly singular (that is, higher-order derivatives do not exist) at points where the pressure gradient vanishes. Numerical simulations of the thin film equation, with either periodic or localized initial condition, are shown to approach the appropriate particular solution. [ABSTRACT FROM AUTHOR]

In this study, a robust non-Newtonian numerical model that can simulate coupled mudflow and sediment transport processes is used to model downstream geomorphic changes during a tailings dam failure. The catastrophic breach of the Mount Polley tailings dam is studied to assess the model performance. Spatial and temporal variation of flow properties like density, viscosity, yield stress, sediment size fractions, and friction are considered in the model. A flexible triangular mesh is adopted, and this helps reduce the computational time significantly compared with structured grid with the same average resolution. High resolution multitemporal digital elevation models (DEMs) are used for the detection of geomorphic changes and estimation of erosion and deposition volumes. The results indicate that the final distribution of tailings deposits obtained from the model results is in good agreement with that obtained from topographic analysis. The model predicted the total volume of erosion and deposition with almost 93% accuracy. The tailings characteristics followed the full Bingham model during the propagation. Different runout scenarios obtained from the mudflow-morphodynamic model and a mudflow fixed-bed model are analyzed, and it was concluded that maximum mudflow depth of the flood wave is higher when bed entrainment is considered. Sediment concentration is higher in the wavefront and middle regions and lower in the tail zone. The mudflow fixed-bed model could underestimate the downstream flood arrival time. The results also confirm that the adopted approach can efficiently model the sediment budget in the study site and the volume of tailings and bed materials released to the downstream lake. Tailings dams are used to store waste solids and water generated during mining operations. Failure of such dams can cause serious damage to human settlements and the downstream environment. For public safety, it is necessary to conduct proper risk assessment, and numerical modeling is crucial for estimating flood magnitude, flood path, and flood arrival time. Tailings water is high in sediment concentration and is viscous; thus, its flow characteristics are different from that of pure water. During the collapse of tailings dam, erosion of the downstream terrain occurs, and changes in the downstream channel morphology can be potentially significant. There can also be a change in the total sediment load when additional solids get eroded from the bed layer. The modeling approach used in this study helps to model erosion and deposition patterns and estimate the downstream flood arrival time when transport of sediment in the downstream channel is considered along with the viscous nature of tailings. When conducting risk assessment of tailings dam failures and when planning for evacuation, this mobile-bed modeling approach can be implemented by design engineers and emergency planners. [ABSTRACT FROM AUTHOR]

Some non-Newtonian fluids have time-dependent rheological properties like a shear stress that depends on the shear history or a stress overshoot that is a function of the resting time, when fluid movement is started. The rheological properties of such complex fluids may not stay constant while they are used in an industrial process, and it is therefore desirable to measure these properties frequently and with a simple and robust device like a pipe rheometer. This paper investigated how the time-dependent rheological properties of a thixotropic and viscoelastic shear-thinning fluid can be extracted from differential pressure measurements obtained at different flowrates along a circular pipe section. The method consists in modeling the flow of a thixotropic version of a Quemada fluid and solving the inverse problem in order to find the model parameters using the measurements made in steady-state conditions. Also, a Maxwell linear viscoelastic model was used to reproduce the stress overshoot observed when starting circulation after a resting period. The pipe rheometer was designed to have the proper features necessary to exhibit the thixotropic and viscoelastic effects that were needed to calibrate the rheological model parameters. The accuracy of rheological measurements depends on understanding the effects that can influence the observations and on a proper design that takes advantage of these side effects instead of attempting to eliminate them. [ABSTRACT FROM AUTHOR]

AbstractThis research article delves into the crucial role that polymers play in controlling the boundary layer flow and heat transfer of non-Newtonian fluids past a stretching surface. To explore the various behaviors of non-Newtonian fluid flow, two classical viscosity models—Reiner–Philippoff and Powell–Eyring—are utilized. Taking into account the microstructure and concentration of polymers, a molecular approach is employed to describe the viscoelasticity effect. Through numerical similarity analysis, the impact of polymers on flow and heat transfer control of non-Newtonian fluids is examined in detail. The article also discusses the behavior of skin friction and the Nusselt number in the presence of polymers. It is observed that the viscosity of the fluid decreases in the vicinity of the surface as the polymers interact with velocity gradients in the boundary layer. However, as the distance from the surface increases, the viscosity returns to its original value. Moreover, the addition of polymers within the non-Newtonian fluid leads to a reduction in heat transport and an enhancement in skin drag. Overall, this study sheds light on the crucial role of polymers in optimizing heat transfer and controlling flow behavior in non-Newtonian fluids. [ABSTRACT FROM AUTHOR]

Introduction: Cerebrospinal fluid (CSF) plays a crucial role in the maintenance of the central nervous system (CNS) by cushioning the brain, providing nutrients, removing interstitial waste, and maintaining homeostasis. Flow characteristics of CSF may significantly contribute to brain dynamics, injury mechanics, disease pathogenesis, and the functionality of the glymphatic system. Conventionally, CSF is considered to have very similar rheological properties to water and Newtonian behavior of CSF has been assumed, despite its complex composition, which can include proteins like albumin and tau, as well as cellular content such as blood. Methods: Recent advances in rheological techniques allow for more accurate quantification of CSF characteristics and behavior. Here, we present an updated rheological characterization of CSF, including the impact of its cellular and proteinaceous constituents. CSF samples were tested for protein and cellular concentration. Using precision torsional rheometry and recently developed extensional rheology techniques, we show that CSF with elevated cellular or protein concentration exhibits significant non-Newtonian behavior, especially at low shear rates. Results: Like other biological fluids, CSF with elevated cellular or protein concentration exhibits shear thinning behavior until reaching a steady state viscosity of approximately 1mPa-s at shear rates greater than 10 s-1. This shear thinning behavior becomes more pronounced with increasing concentration of its constituents. In extensional flow, CSF exhibited weakly non-Newtonian behavior, with an average extensional relaxation time of 0.14 ms. The extensional relaxation time is positively correlated to cellular concentration and significantly increased with elevated protein. Discussion: Our results enhance the understanding of CSF rheology with significant implications for the analysis, modeling, and treatment of CSF-related processes. [ABSTRACT FROM AUTHOR]

By considering the ability of phase change materials (PCMs) in the storage of energy, the melting of four types PCMs including RT22, RT26, RT35, and RT41 in a heat exchanger is examined in this research. The impact of various shell cross‐sectional configurations on the complete melting time of materials, temperature changes, and liquid fraction throughout the melting process are presented. It is assumed that the main heat transfer fluid in the tube is non‐Newtonian and the tube is filled with a porous medium. The enthalpy porosity manner is applied for simulating the process of phase change and the heat natural convection and conduction cases are discussed. On the basis of the obtained results, the decrease in complete melting time is about 20% compared with the absence of a porous medium in the circular cross‐section configuration. The shell configuration has a noticeable impact on the reduction of the required time for melting. In the square cross‐section configuration, RT22 has the lowest melting time, as well as RT41 has the longest melting time in the inverted triangular cross‐section configuration in which the maximum time difference for RT22 is about 77% less. So, the best cross‐section for the shortest complete melting time is square. [ABSTRACT FROM AUTHOR]

Velocities and Shear stress on axial axis. [Display omitted] • This article proposes a novel dynamic meshing technique for peristaltic pumping problems. This numerical technique is based upon finite volume method. • It provides more accurate results when unsteady solutions in fixed coordinates are to be discussed. • Proposed method is applicable to Newtonian as well as non-Newtonian fluid models. • As an application a peristaltic flow of non-Newtonian Quemada fluid is investigated in axisymmetric channel. Introduction: Flow dynamics due to the peristaltic pumping has been the topic of great interest for the researchers. But numerical and analytical analyses for the peristaltic motion are limited where flow domain is deformed real-time. Research on peristalsis has a limitation where theoretical aspects of walls motion are considered, neglecting the real time deformation of the walls. Objectives: This paper aims to propose a more reliable and accurate numerical methodology for peristaltic motions to address the above-mentioned challenge. Stream traces, velocities, and pressure drops along the tube is to be visualized more accurately. Methods: In present study a finite volume based dynamic mesh motion method is adopted to analyze the peristaltic motion of a non-Newtonian Quemada fluid in an axisymmetric channel. The walls and interior domain of the channel is dynamically deformed for a sinusoidal wave traveling on boundary. Results: Simulation of unsteady flow behavior for time t = 0 s to 2 s and amplitude ratio Φ = 0.2 , 0.4 , a n d 0.6. predicts fluid trapping phenomenon. Rotation of fluid particles is more prominent for higher amplitude ratios. Pressure gradient increases with increasing amplitude ratios. Conclusion: A novel dynamic mesh method is proposed for peristaltic pumping. It provides more accurate and more physical results for stream traces; pressure drops and velocities along the tube. A limited case of the study validates the theoretical and analytical results already presented in literature; hence the method is reliable. [ABSTRACT FROM AUTHOR]