Search

Stagnation point flow defines the fluid motion near the stagnation point of a solid surface and has utilization in the process of polymer extrusion, electronic gadgets cooling, nuclear reactor, etc. Furthermore, the main theme of this work is to analyze the heat transfer characteristics of stagnation point flow of Casson nanofluid over stretching sheet using induced magnetic field and Cattaneo-Christov model. The Casson fluid is a non-Newtonian fluid model; and in the current work the working fluid consists of nanoparticles of Au (Gold) and blood (Casson fluid). In the existing model, temperature of the surface depends on the distance from the stagnation point. Therefore, Darcy-Forchheimer porous model is incorporated. The solution of coupled nonlinear PDEs is obtained by bvp4c. The heat transfer and flow characteristics of Au-blood based Casson nanofluid are discussed graphically. The dual behavior is observed in the profiles of induced magnetic field with increase in the value of reciprocal magnetic Prandtl number, however the velocity outlines of Au-blood nanofluid declined. A comparison is presented with previous article and is found to be in good agreement. [ABSTRACT FROM AUTHOR]

The species chemical reaction is an especially significant event in transient fluids. This is a crucial element that raises the temperature as a result of a noticeable rise in reaction rates. Hydrometallurgical industries and chemical engineering, such as the manufacturing of polymers and the processing of food, put a significant amount of concentration with consequences of chemical reactions on heat and mass transport. The effects of chemical reaction, reduced gravity, viscous dissipation, and viscosity on oscillatory heat and mass properties of gravity-driven reactive flow across an inclined heated plate at three positions cos 30 ° , cos 45 ° , and cos 60 ° are the main objective of this work. To elaborate material quantities, the computational mathematical model is developed. The viscosity of fluid is considered as a function of temperature. The non-dimensional model is transformed into non-oscillating and oscillating parts by using Stokes factors. For the convergence of numerical outcomes, the primitive formulation is used. The graphical and numerical findings are obtained through FORTRAN language and Tecplot-360 software. It was found that the velocity of fluid increases for lower values of reaction rate but decreases for higher reaction rate. It can be seen that the significant magnitude of oscillatory heat transfer increases as the Prandtl number increases. It is also examined that amplitude of shearing stress increases at each angle as the reduced gravity increases. The prominent amplitude in the oscillating in heat and mass transfer for minimum viscosity is noted along the inclined heated plate. [ABSTRACT FROM AUTHOR]

The importance of non-Newtonian fluid (Casson fluid) in industry is increasingly appreciated. However, little is known about the flow rheology of Casson fluid flowing over a Riga plate. Thus, the purpose of this investigation is to examine the nature of entropy generation (EG) and heat transfer (HT) on Casson hybrid nanofluid flow past a Riga plate by considering the influences of magnetic field and thermal radiation. The Hamilton–Crosser (Model 1) and Xue model (Model 2) of thermal conductivity are incorporated for Casson hybrid nanofluid. The governing equations are solved by numerical methods i.e., bvp4c and shooting techniques. In the current framework, the comparative patterns for both models of temperature, velocities, EG and Bejan number are depicted due to the existing parameters. The domain of the pertinent parameters is taken as thermal radiation, 4 ≤ R a ≤ 7 ; stretching parameter, 0. 6 ≤ λ ≤ 1 ; Casson factor, 0. 5 ≤ δ ≤ 2 ; rotation parameter, 1 ≤ ℜ t ≤ 4 and Hartmann number, 2 ≤ H a ≤ 1 1. The outcomes show that the rise in volume fraction and thermal conductivity profile of Xue model (Model 2) is better than Hamilton–Crosser model (Model 1). Moreover, EG profiles are escalated with augmentation in values of Hartmann number and stretching parameter for both models. The results of the study are useful for predicting the rheology of right fluid, while it also assists in safeguarding the boundary layer (BL) separation, along with establishing a parallel force to the surface in assisting the domain of science and technology. Mathematical model addressing the three-dimensional flow of Casson hybrid nanofluid over a Riga plate subject to viscous dissipation and linear thermal radiation was investigated. The solution to the governing equations are obtained through two numerical schemes, (i) shooting method and (ii) bvp4c. Effect of the active parameters on entropy generation is discussed through graphs and it was observed that for increasing value of both Hartmann number and stretching parameter the profiles of entropy generation increases. [ABSTRACT FROM AUTHOR]

A numerical investigation of MHD blood flow through a stenosed permeable curved artery has been done in this study. Blood flow is considered in two-phases; core and plasma region, respectively. Viscosity of the core region is considered as temperature-dependent, while constant viscosity is considered in plasma region. The governing equations of the proposed two-phase blood flow model are considered in the toroidal coordinate system. The second-order finite difference method is adopted to solve governing equations with 10 - 6 tolerance in the iteration process. A comparative study of Darcy number (Da) is performed to understand the influence of permeable and impermeable wall conditions. The effect of various physical parameters such as magnetic field (M), viscosity variation parameter ( λ 1 ), Darcy number (Da), heat source (H) and chemical reaction parameter (ξ ) is displayed graphically on the flow velocity, temperature, concentration, wall shear stress and frictional resistance profiles. A comparison with published work has also been displayed through the graph to validate the present model, and it is in fair agreement with the existing work. The present study suggested that the curvature and permeability of the arterial wall raise the risk of atherosclerosis formation, while the implication of heat source on the blood flow lower this risk. [ABSTRACT FROM AUTHOR]

Extensive analysis has recently been presented on the applications of nanofluids in heat transfer developments. The primary concern of this work is to excogitate the flow features of blood flow with the inclusion of gold plated nanoparticles. In this regard, the Casson fluid model was adopted to simulate the transportation of blood flow. The momentum features of flowing fluid are divulged by incorporating magnetization and porosity aspects whereas thermal attributes of concerned flow are anticipated under nonlinearized radiating thermal flux. Formulated governing expressions are transmuted into the system of the nonlinearized ordinary differential structure by implementing appropriate conversion. The solution is headed by implementing an efficient build in routine renowned as bvp4c based on the finite differencing. The impacts of the involved parameters on the resulting dimensionless profiles are discussed thoroughly. The results indicating that the velocity in radial direction declines with augmenting the nanoparticle volume fraction, while the velocity in the azimuthal direction and the temperature upsurge. Besides, the velocities in the radial and azimuthal directions augment due to rotation parameter and the temperature shrinks. [ABSTRACT FROM AUTHOR]

In this paper, the influence of the transverse magnetic field is unraveled on the development of steady flow regime for an incompressible fluid in the boundary layer limit of a semi-infinite vertical plate. The sensitivity of real fluids to changes in temperature suggests a variable thermal conductivity modeling approach. Using appropriate similarity variables, solutions to the governing nonlinear partial differential equations are obtained by numerical integration. The approach used here is based on using the shooting method together with the Runge-Kutta-Fehlberg integration scheme. Representative velocity and temperature profiles are presented at various values of the governing parameters. The skin-friction coefficient and the rate of heat transfer are also calculated for different parameter values. Pertinent results are displayed graphically and discussed. It is found that the heat transfer rate improves with an upsurge in a magnetic field but lessens with an elevation in the fluid thermal conductivity. [ABSTRACT FROM AUTHOR]

The effect of local thermal nonequilibrium (LTNE) on the entropy generation and heat transfer characteristics in the magnetohydrodynamic flow of a couple‐stress fluid through a high‐porosity vertical channel is studied numerically using the higher‐order Galerkin technique. The Boussinesq approximation is assumed to be valid and the porous medium is considered to be isotropic and homogeneous. Two energy equations are considered one each for solid and fluid phases. The term involving the heat transfer coefficient in both equations renders them mutually coupled. Thermal radiation and an internal heat source are considered only in the fluid phase. The influence of inverse Darcy number, Hartmann number, couple‐stress fluid parameter, Grashof number, thermal radiation parameter, and interphase heat transfer coefficient on velocity and temperature profiles is depicted graphically and discussed. The entropy generation, friction factor, and Nusselt number are determined, and outcomes are presented via plots. The effect of LTNE on the temperature profile is found to cease when the value of the interphase heat transfer coefficient is high, and in this case, we get the temperature profiles of fluid and solid phases are uniform. The physical significance of LTNE is discussed in detail for different parameters' values. It is found that heat transport and friction drag are maximum in the case of LTNE and minimum in the case of local thermal equilibrium. We observe that LTNE opposes the irreversibility of the system. The corresponding results of a fluid‐saturated densely packed porous medium can be obtained as a limiting case of the current study [ABSTRACT FROM AUTHOR]

Recent developments in fluid dynamics have been focusing on nanofluids, which preserve significant thermal conductivity properties and magnify heat transport in fluids. Classical nanofluid studies are generally confined to models described by partial differential equations of an integer order, where the memory effect and hereditary properties of materials are neglected. To overcome these downsides, the present work focuses on studying nanofluids with fractional derivatives formed by differential equations with Caputo time derivatives that provide memory effect on nanofluid characteristics. Further, heat transfer enhancement and boundary layer flow of fractional Maxwell nanofluid with single‐ wall and multiple walls carbon nanotubes are investigated. The Maxwell nanofluid saturates the porous medium. Also, buoyancy, magnetic, electric, and heating effects are considered. Governing continuity, momentum, and energy equations involving Caputo time‐fractional derivatives reduced non-dimensional forms using suitable dimensionless quantities. Numerical solutions for arising nonlinear problems are developed using finite difference approximation combined with L1 algorithm. The influence of involved physical parameters on flow and heat transfer characteristics is analyzed and depicted graphically. Our simulations found out that surface drag of Maxwell nanofluid with single‐ walled carbon nanotubes dominates nanofluids with multiple walls carbon nanotubes, but the reverse trend is noticed for larger Grashof number values. [ABSTRACT FROM AUTHOR]

Approximate solutions are given to investigate the problem of heat transfer and flow of a nanofluid between two nonparallel plates. Two different types of carbon nanotube (CNT) nanoparticles, namely functionalized single‐walled carbon nanotubes and functionalized multi‐walled carbon nanotubes are considered with water as the base fluid. The chemical functionalization is attributed to the attachment of the covalent bond of functional groups onto carbon nanotubes. Using the appropriate similarity variables, the model partial differential equations are transformed into ordinary differential equations and tackled analytically via the homotopy perturbation method. Comparison of the obtained results is carried out with those obtained by the previously published in the literature as well as the Runge–Kutta–Fehlberg method and an excellent agreement is achieved. The effects of various emerging parameters on nanofluid velocity, temperature, skin friction coefficient, and Nusselt number are illustrated graphically and comprehensively discussed. [ABSTRACT FROM AUTHOR]

The present article candidly states the incremental impact of nonlinear thermal radiation on heat transfer enhancement due to Darcy–Forchheimer flow of spinel-type MnFe2O4-Casson/water nanofluids due to a stretched rotating disk. In present contest, the entropy generation approach is highlighted specially as a powerful tool for the analysis of the brain function, in accordance with the theological and philosophical approach of Saint Thomas Aquinas. The some of the results of the present study that strengthening of permeability and Casson parameter contribute to the diminution of radial and tangential velocity profiles and yield shrinkage of the related boundary layers. An increase in thermal radiation leading to more heat propagating into the fluid thereby improves the TBL. Fluids with non-Newtonian behavior contribute greater entropy generation rate compared to Newtonian fluids. The most significant outcome is that the entropy generation makes a real contribution to the brain function or analysis of the function of the brain. [ABSTRACT FROM AUTHOR]

The current study focuses on investigating the influence of transverse magnetic field, variable viscosity, buoy-ancy, variable Prandtl number, viscous dissipation, Joulian dissipation, and heat generation on the flow of nanofluids over thin needle moving in parallel stream. The theory of nanofluids that includes the Buongiorno model featured by slip mechanism, such as Brownian motion and thermophoresis, has been implemented. Further, convective boundary condition and zero mass flux condition are considered. The nondimensionally developed boundary layer equations have been solved by Runge–Kutta–Fehlberg method with shooting technique for different values of parameters. The most relevant outcomes of the present study are that the augmented magnetic field strength, viscosity parameter, buoyancy ratio parameter, and the size of the needle undermine the flow velocity, establishing thicker velocity boundary layer while Richardson number and Brownian motion show opposite trend. Another most important outcome is that increase in the size of the needle, viscous dissipation, convective heating, and heat generation upsurges the fluid temperature, leading to improvement in thermal boundary layer. The effects of different natural parameters on wall shear stress and heat and mass transfer rates have been discussed. [ABSTRACT FROM AUTHOR]

Considering the recent aspiration of experts dealing with the painting of aircraft and bonnet of cars to further understand the relevance of skin friction and heat transfer while painting all these objects that are neither horizontal nor vertical, neither a cone/wedge or cylinder but upper horizontal surface of a paraboloid of revolution; a two-dimensional electrically conducting Casson fluid flow on an upper horizontal thermally stratified surface of a paraboloid of revolution is analyzed. The influence of melting heat transfer and thermal stratification are properly accounted for by modifying classical boundary condition of temperature. Plastic dynamic viscosity and thermal conductivity of the fluid are assumed to vary linearly with temperature. In view of this, all necessary models were modified to suit the case T m < T ∞ $T_m

Purpose The purpose of this paper is to investigate the impact of thermal radiation interaction with Hall current, buoyancy force, and oscillatory surface temperature on hydromagnetic-mixed convective heat exchange stream of an electrically conducting nanofluid past a moving permeable plate in a porous medium within a rotating system.Design/methodology/approach Analytical closed-form solutions are obtained for both the momentum and the energy equations using the perturbation method.Findings The effects of various important parameters on velocity and temperature fields within the boundary layer are discussed for three different water-based nanofluids containing copper (Cu), aluminum oxide (Al2O3), and titanium dioxide (TiO2) as nanoparticles. Local skin friction and Nusselt number are illustrated graphically and discussed quantitatively. The results show that Hall current significantly affects the flow system. Results for some special cases of the present analysis are in good agreement with the existing literature.Originality/value The problem is relatively original to study the hydromagnetic-oscillatory flow of a nanofluid with Hall effect and thermal radiation past a vertical plate in a rotating porous medium. [ABSTRACT FROM AUTHOR]

The present study examines the effect of slip and convective boundary condition on magnetohydrodynamic (MHD) stagnation point flow and heat transfer due to Casson nanofluid past a stretching sheet. Similarity transformation is used to convert the nonlinear governing equations and their associated boundary conditions into dimensionless form. The resulting system of ordinary differential equations is then solved numerically using the Runge-Kutta-Fehlberg method along with shooting technique. Numerical results are obtained for velocity, temperature, and concentration distribution as well as for the skin friction coefficient, the local Nusselt number, and Sherwood number. It is found that the local Nusselt number and Sherwood number decrease with an increase in Casson parameter γ. However, the skin friction coefficient -f"(0) increases with an increase in Casson parameter γ and decreases with an increase in velocity ratio parameter A. The results are displayed both in graphical and tabular form to illustrate the effect of the governing parameters on the dimensionless velocity, temperature, and concentration. Then, comparison has been made and found to be in good agreement with a previous published result on special cases of the problem. [ABSTRACT FROM AUTHOR]

This article examines the combined effects of buoyancy force and asymmetrical convective cooling on unsteady MHD channel flow and heat transfer characteristics of an incompressible, reactive, variable viscosity and electrically conducting third grade fluid. The chemical kinetics in the flow system is exothermic and the asymmetric convective heat transfers at the channel walls follow the Newton's law of cooling. The coupled nonlinear partial differential equations governing the problem are derived and solved numerically using a semi-implicit finite difference scheme. Graphical results are presented and physical aspects of the problem are discussed with respect to various parameters embedded in the system. [ABSTRACT FROM AUTHOR]

This paper investigates numerically the effects of variable viscosity on unsteady generalized Couette flow of a water base nanofluid with convective cooling at the moving surface. The Buongiorno model utilized for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The nonlinear governing equations of continuity, momentum, energy and nanoparticles concentration are tackled numerically using a semi discretization finite difference method together with Runge-Kutta Fehlberg integration scheme. Numerical results for velocity, temperature, and nanoparticles concentration profiles together with skin friction and Nusselt number are obtained graphically and discussed quantitatively. [ABSTRACT FROM AUTHOR]

An investigation of the magnetohydrodynamics (MHD) boundary layer slip flow over a vertical stretching sheet in nanofluid with non-uniform heat generation/absorbtion in the presence of a uniform transverse magnetic field has been carried out. The governing non-linear partial differential equations are transformed into a system of coupled non-linear ordinary differential equations using similarity transformations and then solved numerically using the Runge-Kutta fourth order method with shooting technique. Numerical results are obtained for the fluid velocity, temperature as well as the shear stress and the rate of heat transfer at the surface of the sheet. The results show that there are significant effects of various pertinent parameters on velocity and temperature profiles. [ABSTRACT FROM AUTHOR]

Heat transfer characteristics of a Berman flow of water based nanofluids containing copper (Cu) and alumina (Al2O3) as nanoparticles in a porous channel with Navier slip, viscous dissipation, and convective cooling are investigated. It is assumed that the exchange of heat with the ambient surrounding takes place at the channel walls following Newton's law of cooling. The governing partial differential equations and boundary conditions are converted into a set of nonlinear ordinary differential equations using appropriate similarity transformations. These equations are solved analytically by regular perturbation methods with series improvement technique and numerically using an efficient Runge-Kutta Fehlberg integration technique coupled with shooting scheme. The effects of the governing parameters on the dimensionless velocity, temperature, skin friction, pressure drop, and Nusselt numbers are presented graphically and discussed quantitatively. [ABSTRACT FROM AUTHOR]

Heat and mass transfer in the slip flow of a viscous incompressible fluid over flat isothermal linearly stretching sheet, in presence of transverse magnetic field, is investigated. The sheet reacts with the flowing fluid and inert specie is produced that diffuses inside the boundary layer. The mass flux of the specie at the plate is taken directly proportional to specie concentration at the plate. The governing equations of continuity, momentum, energy and specie diffusion are transformed into ordinary differential equation using suitable transformations. The system of nonlinear ordinary differential equations is obtained and solved numerically using Runge-Kutta method along with shooting technique. The velocity, heat and specie concentration distribution are obtained for different parameters and presented through figures. Skin-friction coefficient, Nusselt number and Sherwood number at plate for various physical parameters are discussed numerically and presented through tables. [ABSTRACT FROM AUTHOR]

Thesteady stagnation-point flow and heat transfer of an electrically conducted incompressible viscous fluid are extended to the case where the disk surface is convectively heated and radially stretching. The fluid is subjected to an external uniform magnetic field perpendicular to the plane of the disk. The governing momentum and energy balance equations give rise to nonlinear boundary value problem. Using a spectral relaxation method with a Chebyshev spectral collocation method, the numerical solutions are obtained over the entire range of the physical parameters. Emphasis has been laid to study the effects of viscous dissipation and Joule heating on the thermal boundary layer. Pertinent results on the effects of various thermophysical parameters on the velocity and temperature fields as well as local skin friction and local Nusselt number are discussed in detail and shown graphically and/or in tabular form. [ABSTRACT FROM AUTHOR]

This study aims to analyze the effects of thermal buoyancy on the laminar boundary layer about a vertical plate in a uniform stream of fluid under a convective surface boundary condition. Using a similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically by applying shooting iteration technique together with fourth-order Runge-Kutta integration scheme. The variations in dimensionless surface temperature and fluid-solid interface characteristics for different values of Prandtl number (Pr), local Grashof number Grx, and local convective heat transfer parameter Bix are graphed and tabulated. A comparison with previously published results on special case of the problem shows excellent agreement. [ABSTRACT FROM AUTHOR]

This study examines the effects of viscous and porous dissipation on entropy generation in the viscoelastic fluid flow induced by a linearly stretching surface. Analysis of mass transfer is also performed. Consideration of rheological characteristics of viscoelastic fluid in the energy conservation law and entropy generation number in terms of viscous dissipation makes a striking difference in the energy equation and entropy generation number for Newtonian and viscoelastic fluid. This important concern which is yet not properly attended is also be examined in the present study. The dimensional governing equations are reduced to a set of self-similar differential equations. The energy and concentration equations are solved exactly by employing the Laplace transform technique. The obtained exact solutions of reduced set of governing equations are utilized to compute the entropy generation number. To analyze the impacts of flow parameter on velocity profile, temperature distribution, concentration profile, and entropy generation number inside the boundary layer, graphs are plotted and discussed physically. The permeability and viscoelastic parameters have strong influence on the entropy generation in the vicinity of stretching surface. [ABSTRACT FROM AUTHOR]

In this article, the authors of the article "Mixed Convection From a Convectively Heated Vertical Plate to a Fluid With Internal Heat Generation" argues over discussion on their paper by researcher Asterios Pantokratoras, published in the "Journal of Heat Transfer," in 2011. It presents a mathematical equation related to internal heat generation within the cold fluid in contact with the right surface of the plate used for obtaining local similarity equation for energy balance.

The problem of steady laminar hydromagnetic heat transfer by mixed convection flow over a vertical plate embedded in a uniform porous medium in the presence of a uniform normal magnetic field is studied. Convective heat transfer through porous media has wide applications in engineering problems such as in high temperature heat exchangers and in insulation problems. We construct solutions for the free convection boundary-layer flow equations using an Adomian-Padé approximation method that in the recent past has proven to be an able alternative to the traditional numerical techniques. The effects of the various flow parameters such as the Eckert, Hartmann, and Schmidt numbers on the skin friction coefficient and the concentration, velocity, and temperature profiles are discussed and presented graphically. A comparison of our results with those obtained using traditional numerical methods in earlier studies is made, and the results show an excellent agreement. The results demonstrate the reliability and the efficiency of the Adomian-Padé method in an unbounded domain. [ABSTRACT FROM AUTHOR]

The article focuses on research related to magnetohydrodynamic (MHD) flow in a vertical channel consisting of porous medium in the presence of Hall current and thermal radiation effects. It mentions the application of magnetic field of uniform strength to channel walls in perpendicular direction and induction of heat transfer due to temperature difference. It also mentions the effect of medium's porosity on the fluid velocity components and the graphical representation of velocity field.

A mathematical model of convective steady flow over rotating disks in an orthotropic porous medium has been developed and solved the non-dimentional governing equations for flow by the shooting method that uses fourth order Runge- Kutta integration technique and Newton's method. Magnitude of radial velocity of fluid decreases near the surfaces of the disks for increasing value of Reynolds number. Impact of stretching parameters on the radial and tangential velocity profiles is observed. Computational results are presented graphically for various cases of parameters on velocity (radial f' and tangential g ) and temperature profiles and table values are reported for skin friction and Nusselt number along both disks. It is observed that as the Reynolds number increases, the tangential velocity decreases. As we move far away from the disk the effects of physical parameters is not significant. It is seen that when the stretching parameter increases the radial velocity increases initially and when η=0.3 onwards the radial velocity decreases. This type of study finds application in industrial and engineering fields such as turbine engines and electronic power generating systems etc. [ABSTRACT FROM AUTHOR]