Cattaneo–Christov heat flux model for nanofluid flow over a curved stretching sheet: An application of Stefan blowing

The present work investigates the thermophoresis and Brownian motion effects in nanofluid flow over a curved stretching sheet (CSS). Also, the Cattaneo–Christov heat flux and Stefan blowing (SB) conditions are considered for studying heat and mass transport characteristics. The present work's novelty is associated with considerations of convective boundary and SB conditions in nanomaterial flow over a CSS. The coupled partial differential equations are changed to ordinary differential equations by employing suitable similarity variables, and the resultant model is numerically handled using Runge–Kutta–Fehlberg's fourth fifth-order method with the shooting scheme. The stimulation of the involved parameters/numbers on the flow, mass, and heat fields is broadly deliberated using suitable graphs. The present analysis's significant relevant outcomes are that the inclination in thermophoresis and Brownian motion parameters increases the heat transfer. The inclined values of the Brownian motion parameter decay the mass transfer. Furthermore, the increased values of both Schmidt number and SB parameter drop the mass transport. The increased values of the Brownian motion parameter and Schmidt number decays the rate of mass transference.     

Influence of Viscous Dissipation on Mixed Convection in a Non‐Darcy Porous Medium Saturated with a Nanofluid

In this study, the effects of viscous dissipation on mixed convection heat and mass transfer along a vertical plate embedded in a nanofluid‐saturated non‐Darcy porous medium have been investigated. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The new far‐field thermal boundary condition that has been recently developed is employed to properly account for the effect of viscous dissipation in mixed convective transport in a porous medium. The nonlinear governing equations and the associated boundary conditions are transformed to a set of nonsimilar ordinary differential equations and the resulting system of equations is then solved numerically by an improved implicit finite‐difference method. The effect of the physical parameters on the flow, heat transfer, and nanoparticle concentration characteristics of the model are presented through graphs and the salient features are discussed. As expected, a significant improvement in the heat transfer coefficient is noticed because of the consideration of the nanofluid in the porous medium. With the increase in the value of the viscous dissipation parameter, a reduction in the non‐dimensional heat transfer coefficient is noted while an increase in the nanoparticle mass transfer coefficient is seen. Further, an increase in the mixed convection parameter lowered both the heat and nanoparticle mass transfer rates. Moreover, the increase in the Brownian motion parameter enhanced the nanoparticle mass transfer rate but it reduced the heat transfer rate in the boundary layer. A similar trend is also found with the thermophoresis parameter. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(5): 397–411, 2014; Published online 3 October 2013 in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21083     

Heat and Mass Transfer Flow of a Nanofluid over an Inclined Plate under Enhanced Boundary Conditions with Magnetic Field and Thermal Radiation

This article presents the magnetohydrodynamic boundary layer flow, heat and mass transfer characteristics of a nanofluid over an inclined porous vertical plate with thermal radiation and chemical reaction. The new enhanced concentration boundary condition on the surface of the wall is considered in this analysis. The governing nonlinear partial differential equations are transformed into a system of nonlinear ordinary differential equations using the similarity variables and are solved numerically using the finite element method. The effect of key parameters such as magnetic parameter (M), buoyancy ratio (Nr), Prandtl number (Pr), thermal radiation (R), Brownian motion (Nb), thermophoresis (Nt), Lewis number (Le), and chemical reaction parameter (Cr) on velocity, temperature, and concentration distributions is discussed in detail and the results are shown graphically. Furthermore, the impact of these parameters on skin‐friction coefficient, Nusselt number, and Sherwood number is also investigated and the results are shown in tabular form. The developed algorithm is validated with works published previously and was found to be in good agreement. The thermal boundary layer thickness is elevated, whereas the solutal boundary layer thickness retards with the improving values of the Brownian motion parameter (Nb). The rates of nondimensional temperature and concentration both decelerate with higher values of the thermophoresis parameter (Nt).     

Influence of wall properties on the peristaltic flow of a nanofluid: Analytic and numerical solutions

This study is concerned with the peristaltic transport of nanofluid in a channel with complaint walls. Transport equations involve the combined effects of Brownian motion and thermophoretic diffusion of nanoparticles. Mathematical modeling is carried out by utilizing long wavelength and low Reynolds number assumptions. The coupled nonlinear boundary value problem (BVP) has been solved numerically by using shooting technique through software Mathematica. The analytic solutions are computed by a robust analytical tool namely the homotopy analysis method (HAM). Attention has been focused on the behaviors of Brownian motion parameter (Nb), thermophoresis parameter (Nt), Prandtl number (Pr) and Eckert number (Ec). The results indicate an appreciable increase in the temperature and nanoparticles concentration with the increase in the strength of Brownian motion effects. Further heat transfer coefficient is a decreasing function of Nb and Nt.     

Magnetized impacts of Brownian motion and thermophoresis on unsteady squeezing flow of nanofluid between two parallel plates with chemical reaction and Joule heating

Present research article investigate the heat and mass transfer characteristics of unsteady magnetohydrodynamic Casson nanofluid flow between two parallel plates under the influence of viscous dissipation and first order homogeneous chemical reaction effects. The impacts of thermophoresis and Brownian motion are accounted in the nanofluid model to disclose the salient features of heat and mass transport phenomena. The present physical problem is examined under the presence of Lorentz forces to investigate the effects of magnetic field. Further, the viscous and Joule dissipation effects are considered to describe the heat transfer process. The non‐Newtonian behaviour of Casson nanofluid is distinguished from those of Newtonian fluids by considering the well‐established rheological Casson fluid model. The two‐dimensional partial differential equations governing the unsteady squeezing flow of Casson nanofluid are coupled and highly nonlinear in nature. Thus, similarity transformations are imposed on the conservation laws to obtain the nonlinear ordinary differential equations. Runge‐Kutta fourth order integration scheme with shooting method and bvp4c techniques have been used to solve the resulting nonlinear flow equations. Numerical results have been obtained and presented in the form of graphs and tables for various values of physical parameters. It is noticed from present investigation that, the concentration field is a decreasing function of thermophoresis parameter. Also, concentration profile enhances with raising Brownian motion parameter. Further, the present numerical results are compared with the analytical and semianalytical results and found to be in good agreement.     

Energy and mass transport of micropolar nanofluid flow over an inclined surface with Keller-Box simulation

In this article, micropolar nanofluid boundary layer flow over a slanted stretching surface with Soret and Dufour effect is studied. The inclined stretching surface in this study is considered permeable and linear. In this problem, the Buongiorno model is considered for thermal efficiencies of fluid flow in the existence of Brownian movement and thermophoresis properties. The nonlinear problem for Micropolar Nanofluid flow over the slanted channel is developed to think about the heat and mass exchange phenomenon by incorporating portent flow factors to strengthened boundary layers. In this study, nonlinear partial differential equations are converted to nonlinear ordinary differential equations by utilizing appropriate similarity transformations then elucidated the numerical outcomes by the Keller-Box technique. An examination of the set-up results is performed with accessible outcomes and perceived in a good settlement without involved impacts. Numerical and graphical outcomes are additionally displayed in tables and charts.     

Characteristics of MHD nanofluid flow towards a vertical cone under convective cross-diffusion effects through numerical solutions

In this study, the aim is to find the numerical solutions of steady, two-dimensional, incompressible, viscous, electrically conducting magnetohydrodynamic (MHD) boundary-layer nanofluid flow towards a vertical cone in the presence of thermal diffusion, diffusion thermo, thermophoresis, and Brownian motion effects subject to porous medium and convective boundary condition. For this investigation, the method of similarity transformations is used for the objective of converting nonlinear partial differential equations into the system of ordinary differential equations. Approximate solutions are obtained using a numerical method of the Runge–Kutta method with the shooting technique for the flow, heat, and mass transfer equations together with boundary conditions. For this flow, the impact of various engineering parameters on MHD, thermal, and solutal boundary layers is investigated and the results are displayed graphically. In addition, the numerical values of the local skin-friction coefficient, rate of heat transfer, and rate of mass transfer coefficients are calculated, and the results are presented numerically. Finally, the comparison with previously published work is made and found in good agreement.     

Behavior of slip boundary conditions for the flow of nanofluid in the presence of an inclined magnetic field

The inflated heat transport rate of nanofluids is of great interest to researchers. Conviction of nanosuspension with an enhanced model under the consideration of inclined magnetic field is also vital for the enhancement of heat transport rate. Therefore, in this article, an inclined magnetic field has been considered during a boundary layer flow over an extending sheet, with the sheet being permeable. The sequels of heat radiation, thermophoresis, and Brownian parameters are also taken into consideration in this study. The importance of the study is the slip boundary conditions used for velocity, temperature, and concentration. A set of nonlinear partial differential equations is transformed into ordinary differential equations with a suitable choice of similarity variables. The set of first-order differential equations is quite difficult to solve analytically. Therefore, the numerical Runge-Kutta-Fehlberg method, accompanied with shooting technique, is used. The results of the physical components characterizing the flow phenomena, such as magnetic parameter, thermal radiation, thermophoresis, Brownian parameter, and slip parameters, are elaborated through graphs. The numerical results of physical quantities of attention are presented in tables. The existing outcome conforms to that of the previous published result in a particular case.     

Heat transfer and buoyancy‐driven convective MHD flow of nanofluids impinging over a thin needle moving in a parallel stream influenced by Prandtl number

The current study focuses on investigating the influence of transverse magnetic field, variable viscosity, buoyancy, 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.     

Melting heat transfer analysis of electrically conducting nanofluid flow over an exponentially shrinking/stretching porous sheet with radiative heat flux under a magnetic field

Modern magnetic nanomaterial processing operations are progressing rapidly and require increasingly sophisticated mathematical models for their optimization. Stimulated by such developments, in this paper, a theoretical and computational study of a steady magnetohydrodynamic nanofluid over an exponentially stretching/shrinking permeable sheet with melting (phase change) and radiative heat transfer is presented. Besides, wall transpiration, that is, suction and blowing (injection), is included. This study deploys Buongiorno's nanofluid model, which simulates the effects of the Brownian motion and thermophoresis. The transport equations and boundary conditions are normalized via similarity transformations and appropriate variables, and the similarity solutions are shown to depend on the transpiration parameter. The emerging dimensionless nonlinear coupled ordinary differential boundary value problem is solved numerically with the Newton-Fehlberg iteration technique. Validation with special cases from the literature is included. The increase in the magnetic field, that is, the Hartmann number, is observed to elevate nanoparticle concentration and temperature, whereas it dampens the velocity. Higher values of the melting parameter consistently decelerate the boundary layer flow and suppress temperature and nanoparticle concentration. A higher radiative parameter strongly increases temperature (and thermal boundary layer thickness) and weakly accelerates the flow. The increase in the Brownian motion reduces nanoparticle concentrations, whereas a greater thermophoretic body force strongly enhances them. The Nusselt number and Sherwood number are observed to be decreased with an increasing Hartmann number, whereas they are elevated with a stronger wall suction and melting parameter.     

Multiple convection‐driven Falkner‐Skan flow of Carreau nanofluid along a permeable wedge: An analytical approach

The impression of multiple convective conditions on Falkner‐Skan flow along a permeable static/moving wedge is demonstrated here. The Carreau nanofluid model depending on the power law index is incorporated with the effects of thermophoresis and Brownian motion. A suitable similarity conversion is consumed to bring out the nonlinear ordinary differential equations (ODEs) from the partial differential system. The transformed system is tackled via analytical and numerical procedure by homotopy perturbation method and RK‐5 with shooting technique, respectively. Numerical computations assert that the growth of concentration and temperature boundary layer widths are in an inversely proportional relation to the permeability of the medium, whereas reverse effect is observed for conduction convection and conduction diffusion parameters. Also, with the enhancement of Brownian motion parameter, the rate of heat transport gets reduced for static wedge by 14.25% whereas for moving wedge the reduction is 10.61%. Another significant observation shows that the growth in mass transport with conduction diffusion is 17.65% greater for moving wedge in contrast to static one in accordance with other governing parameters.     

Numerical computation on Marangoni convective flow of two‐phase MHD dusty nanofluids under Brownian motion and thermophoresis effects

The current theoretical study describes the Marangoni thermal convective flow of magnetohydrodynamic dusty nanofluids along a wavy vertical surface. The two‐phase mathematical model is developed under the influence of thermal radiation and exponentially varying space‐dependent heat source. Pure and hybrid nanoparticles together with dust particle suspension in the base fluid are taken into consideration to characterize the behavior of the flow. Brownian motion and thermophoresis mechanisms are considered, since it enhances the convection features of dusty nanofluid. Appropriate transformations are adopted to modify the flow governing equations and boundary conditions to dimensionless form. The forward finite difference scheme is implemented to illustrate the resultant coupled partial differential equations. The Newton quasi‐linearization technique is utilized to reduce the nonlinear system into a linear form, which is solved thereafter by Thomas algorithm. The responses of velocity, temperature, concentration, friction factor, and heat and mass transfer rate profiles with various governing parameters are discussed and portrayed graphically. The study evidences that the radiation and space‐dependent heat generating parameters strengthen the temperature distribution. Also, the heat transfer rate appreciably rises with the increment in Marangoni convection. The solution methodology and accuracy of the model is validated by generating the earlier outcomes for nonradiating nanofluid flow without heat source/sink.     

Gyrotactic microorganisms bioconvection in combined convective magnetohydrodynamic Casson nanofluid flow over a vertically surfaced saturated porous media with variable viscosity

The current article focuses on mass and thermal transfer analysis of a two-dimensional immovable combined convective nanofluid flow including motile microorganisms with temperature-dependent viscosity on top of a vertical plate through a porous medium, and a model has been developed to visualize the velocity slip impacts on a nonlinear partial symbiotic flow. The governed equations include all of the above physical conditions, and suitable nondimensional transfigurations are utilized to transfer the governed conservative equations to a nonlinear system of differential equations and obtain numerical solutions by using the Shooting method. Numerical studies have been focusing on the effects of intricate dimensionless parameters, namely, the Casson fluid parameter, Brownian motion parameter, thermophoresis parameter, Peclet number, bioconvection parameter, and Rayleigh number, which have all been studied on various profiles such as momentum, thermal, concentration, and density of microorganisms. The concentration boundary layer thickness and density of microorganisms increased as the Casson fluid parameter, Brownian and thermophoresis parameters increased, whereas the bioconvection parameter, Peclet number, and Rayleigh number increased. The thermal boundary layer thickness, concentration boundary layer thickness, and density of microorganisms all decreased. The velocity distribution decreases as the Peclet number, bioconvection, and thermophoresis parameters rise but rises as the Rayleigh number, Brownian motion parameter, and Casson fluid parameter rise. These are graphed via plots along with divergent fluid parameters.     

Darcy–Forchheimer MHD radiative flow through a porous space incorporating viscous dissipation,heat source,and chemical reaction effect across an exponentially stretched surface

The impacts of viscous dissipation, Brownian motion, and the thermophoresis caused by temperature gradient on the steady two-dimensional incompressible chemically reactive and radiative flow of traditional fluid through an exponentially stretched sheet embedded in a Darcy porous media are explored by approaching boundary layer analysis. A magnetic field effect is also addressed along the transverse direction of the horizontal stretched sheet. With the implementation of some suitable nondimensional quantities, the regulating nonlinear partial differential equations, which represent the flow geometry, are transformed into coupled nonlinear ordinary differential equations. To acquire the numerical findings from this set of equations, a three-stage Lobatto IIIa, in-built MATLAB scheme named, Bvp4c is used. The effects of the dimensionless physical factors on the flow, heat, and concentration profile, as well as on the coefficient of drag force and the rate of thermal and mass transit at the surface, are graphically and numerically depicted. The thermal profile, as well as the magnitude of the coefficient of the drag force and the Sherwood number, is found to be escalated with the Darcy–Forchheimer factor, but the depreciation in the value of temperature gradient at the wall is noticed for the same.     

Radiative flow of micropolar nanofluid accounting thermophoresis and Brownian moment

This article describes the Brownian motion and thermophoresis aspects in nonlinear flow of micropolar nanoliquid. Stretching surface with linear velocity creates the flow. Energy expression is modeled subject to consideration of thermal radiation phenomenon. Effect of Newtonian heating is considered. The utilization of transformation procedure yields nonlinear differential systems which are computed through homotopic approach. The important features of several variables like material parameter, conjugate parameter, Prandtl number, Brownian motion parameter, radiation parameter, thermophoresis parameter and Lewis number on velocity, micro-rotation velocity, temperature, nanoparticles concentration, surface drag force and heat and mass transfer rates are discussed through graphs and tables. The presented analysis reveals that the heat and mass transfer rates are enhanced for higher values of radiation and Brownian motion parameters. Present computations are consistent with those of existing studies in limiting sense.     

Effects of the viscous dissipation and chemical reaction on Casson nanofluid flow over the permeable stretching/shrinking sheet

A steady two‐dimensional Casson nanofluid flow over the permeable stretching/shrinking sheet along the viscous dissipation and the chemical reaction is studied in this article. The convective boundary condition is incorporated in energy equation. Similarity variables are applied to convert the governing partial differential equations into ordinary differential equations. The numerical solutions of the equations are obtained by using the shooting method with Maple implementation. The numerical findings indicate occurrence of the dual solutions for a certain range of stretching/shrinking and suction parameters. Therefore, a stability analysis is done to find the solution that is stable and physically realizable. The effects of the pertinent physical parameters on velocity, temperature, and concentration profiles are investigated graphically. Numerical results of various parameters involved for skin friction coefficient, the local Nusselt as well as Sherwood numbers are determined and also discussed in detail. The Casson and suction parameters decrease the velocity in the first solution, whereas they increase it in the second solution. The rate of heat transfer increases in both solutions with an increment in Eckert number, Biot number, thermophoresis, and Brownian motion parameters. Thermophoresis and Brownian motion parameters show opposite behavior in the nanoparticle's concentration. The nanoparticle concentration decreases in both solutions with increment in Schmidt number, Brownian motion, and chemical reaction parameters.     

Magnetically driven chemically reactive Casson nanofluid flow over curved surface with thermal radiation

During this exploration, Casson nanofluid is taken over a sheet that is curved and stretching in nature and its flow equations are analyzed. Radiation and slip provisions are also taken into consideration. A magnetic field of uniform rate is provided. Convective heat and mass transference extract dominant conclusions from the system. The Brownian migration together with thermophoresis is also included in the flow structure. Moreover, the chemical reaction of higher-order within the nanoingredients also generates interest. Guiding equations furnished by the selected model are resettled to ordinary differential equations of nonlinear type by significant similarity transformation. We have worked on MAPLE-19 software to work out this with a suitable accuracy rate. Upshots are shown with diagrams and tables. Corresponding physical consignment such as Nusselt number has been analyzed. Determination of skin friction and moreover Sherwood's number is also in the area of interest. Magnificent advancement in heat sifting is dealt with by magnetic and Brownian motion specification. The graphs prescribed the upshots of thermophoresis and slip parameters. Outcomes convey that temperature together with concentration are reduced for stretching parameters but velocity lines are enhanced. Heat transport goes up for magnetic and Brownian motion framework but elevated outcomes are spotted for radiative flow in contrast to nonradiative flow. Mass transfer is reduced for chemical reaction components but the rate of augmentation is elevated for higher-order chemically reactive flow. Mass Biot number and temperature Biot number both increase the concentration and temperature transport, respectively.     

Thermal diffusion and diffusion thermo effects of Eyring‐Powell nanofluid flow with gyrotactic microorganisms through the boundary layer

In this article, the effects of thermal diffusion and diffusion thermo on the motion of a non‐Newtonian Eyring Powell nanofluid with gyrotactic microorganisms in the boundary layer are investigated. The system is stressed with a uniform external magnetic field. The problem is modulated mathematically by a system of a nonlinear partial differential equation, which governs the equations of motion, temperature, the concentration of solute, nanoparticles, and microorganisms. This system is converted to nonlinear ordinary differential equations by using suitable similarity transformations with the appropriate boundary conditions. These equations are solved numerically by using the Rung‐Kutta‐Merson method with a shooting technique. The velocity, temperature, concentration of solute, nanoparticles, and microorganisms are obtained as functions of the physical parameters of the problem. The effects of these parameters on these solutions are discussed numerically and illustrated graphically through figures. It is found that the velocity decreases with the increase in the non‐Newtonian parameter and the magnetic field, whereas, the velocity increases with a rise in thermophoresis and Brownian motion. Also, the temperature increases with an increase in the non‐Newtonian parameter, magnetic field, thermophoresis, and Brownian motion. These parameters play an important role and help in understanding the mechanics of complicated physiological flows.     

Effect of thermophoresis and Brownian motion on the melting heat transfer of a Jeffrey fluid near a stagnation point towards a stretching surface: Buongiorno's model

This analysis intends to address the coupled effect of phase change heat transfer, thermal radiation, and viscous heating on the MHD flow of an incompressible chemically reactive nanofluid in the vicinity of the stagnation point toward the stretching surface, taking a Jeffrey fluid as the base fluid. Convergent analytical solutions for the nonlinear boundary layer equations are obtained by the successive application of scaling variables and the highly efficacious homotopy analysis method. Error analysis is implemented to endorse the convergence of the solutions. Through parametric examination, influence of various physical parameters occurring in analysis of the profiles of velocity, temperature, and nanoparticle concentration, coefficient of surface drag, rates of mass and heat transfer is explored pictorially. The Deborah number and the melting parameter are found to enhance velocity, and the associated momentum boundary layers are thicker, whereas the magnetic field depreciates the flow rate. Temperature is observed to enhance with the thermophoresis parameter, Prandtl number and Eckert number, whereas a reduction is seen with the thermal radiation parameter and Brownian motion parameter. Nanoparticle concentration is depleted by the chemical reaction parameter, the thermophoresis parameter, and the Lewis number.     

A model for entropy generation in stagnation‐point flow of non‐Newtonian Jeffrey,Maxwell, and Oldroyd‐B nanofluids

We present a generalized model to describe the flow of three non‐Newtonian nanofluids, namely, Jeffrey, Maxwell, and Oldroyd‐B nanofluids. Using this model, we study entropy generation and heat transfer in laminar nanofluid boundary‐layer stagnation‐point flow. The flow is subject to an external magnetic field. The conventional energy equation is modified by the incorporation of nanoparticle Brownian motion and thermophoresis effects. A hydrodynamic slip velocity is used in the initial condition as a component of the stretching velocity. The system of nonlinear equations is solved numerically using three different methods, a spectral relaxation method, spectral quasilinearization method, and the spectral local linearization method, first to determine the most accurate of these methods, and second as a measure to validate the numerical simulations. The residual errors for each method are presented. The numerical results show that the spectral relaxation method is the most accurate of the three methods, and this method is used subsequently to solve the transport equations and thus to determine the empirical impact of the physical parameters on the fluid properties and entropy generation.