Search

Incorporation of momentum gradients produced due to inertial motion of the lid along with the presence of temperature differences in the configuration make the physical problem more significant. The joint variation of momentum and thermal diffusion in diversified natural liquids is recognized as mixed convection. Valuable attention has been received by such a phenomenon in different areas of science and technology such as in wind current --based solar receivers, electronic instruments, control of emergency shutdown in reactors, thermal exchangers, oceanic currents, control of atmospheric pollution, and so on. So, the main focus is to contemplate hydrothermal characteristics of a power-law fluid contained in a square cavity with themovement of the upper lid and being thermally adiabatic. The other extremities are considered to be at rest, and the base wall is prescribed with uniform/nonuniform temperature distributions. The governing formulation of the problem is handled by executing a finite element approach. Hybrid meshing is performed for domain discretization, and weak variational formulation is utilized for formulation discretization. Second-degree polynomials are employed as the interpolation function, providing information about velocity and temperature distributions at boundary and intermediate nodes. The system of finalized non-linear equations is resolved by using the Paradiso software. The results for velocity and temperature distributions are attained comparatively for uniformly and non-uniformly heated profiles. The kinetic energy and average Nusselt number are also computed against flow concerning variables. From the attained graphical and tabular data, it is deduced that by increasing the Reynolds number, inertial forces dominate over buoyancy forces and the effect of lid movement is prominent on flow characteristics. It is also inferred that for the shear thickening case and for all values of the Reynolds number, the average Nusselt number shows a constant behavior. [ABSTRACT FROM AUTHOR]

Current communication is addressed to elaborate features of laminar fluid flowing through a channel with permeable boundaries which is an important flow problem in real-world applications. In this work, Newtonian fluid (base fluid) in a rotating porous contracting/expanding channel with induction of TiO2-Cu nanoparticles (Suspensions) of different shapes and sizes is obliged. Formulation is executed under implementing boundary layer approach. Empirical relation representing features of nanoparticles are added in equations. Afterwards, partial differential expressions are changed into ODE's by incorporating transformations. Solution is heeded by collaboration of R–K and shooting procedure. The impact of flow-controlling parameters is interpreted via graphs and tables. The important quantities of engineering interest like heat flux coefficient, skin friction against different parameters are explained in tabulated manner. To make results more credible different range of nanoparticles volumetric fractions (1–4)%, and different shapes of particles like, i.e., triangle, oval, prism, hexagonal, spherical, brick, cylinders, and platelets are considered. It is inferred from investigation that magnitude of heat transfer coefficient has gained optimization against concerning parameters for the platelet shape of nanoparticles. It is revealed that magnitude of wall drag force and heat flux at lower boundary of channel is more inthe case of contraction than to the expansion of channel. [ABSTRACT FROM AUTHOR]

• It is found that average Nusselt number elevates against escalation in the magnitude of Rayleigh number (Ra) and hybrid nanoparticles volume fraction (ϕ) whereas, opposite trend is depicted against Hartmann number (Ha). • Heat transfer coefficient is found to be more in the situation when star shaped cylinder is installed in comparison to circular and square cylinders. • Positive trend in total entropy is depicted against elevation in Rayleigh number (Ra) and volume fraction of hybrid nanoparticles (ϕ) whereas, decrement is demonstrated against Hartmann number (Ha). • Average Bejan number increases up to 8% against upsurge in the magnitude of hybrid nanoparticles volume fraction (ϕ) and experiences 50% decrement against Rayleigh number (Ra). • Lowest value of ECOP is attained in the absence of hybrid nanoparticles (ϕ = 0) whereas, contrasting aptitude is observed in the situation when magnetic force is absence (Ha = 0). • Maximum magnitude of velocity is attained at wave number (N = 4) whereas, maximum heat is transferred at wave number (N = 5). This article aims to simulate optimum thermal convection and minimization in entropy generation in viscous hybrid nanofluid (Fe 3 O 4 -MWNTs/H 2 O) flow in thermally cold star shaped enclosure and containing heated cylinder. Shape effect of cylinder in managing associated hydrothermal attributes is also interrogated. Physical aspect of magnetic field making angle of inclination with domain is accounted. Formulation of transport equations is expressed in the form of dimensionless partial differential setup containing the thermophysical relations of induced hybrid nanoparticles. The constructed flow issue has been simulated by using Galerkin finite element method (G-FEM) with appliance of COMSOL Multiphysics® software computer package. Results and grid convergence assessment tests are also executed in the study. Significant impact of flow controlling parameters on velocity, temperature and entropy generation profiles has been presented in graphical and tabular manner. Variation is three different types of entropies namely, viscous, thermal and magnetic are estimated. Quantities of interest like, total entropy, average Nusselt and Bejan numbers are also calculated against the sundry parameters. Ecological coefficient of performance which measures the efficiency of physical systems is interrogated which is important physical quantity in practical problems. It is inferred from the outcomes that induction of hybrid nanoparticles (Fe 3 O 4 − MWCNT) produces considerable augmentation of thermal attributes of base fluid. Moreover, it is depicted that average Nusselt number exceeds up to 26.5 % for star shaped inner cylinder in comparison to the square cylinder. Increment up to 6 % in average Nusselt number and 2.19 % decrease in entropy is depicted when hybrid nanoparticles are added in the base fluid (ϕ ≠ 0) in comparison to the situation when nanoparticles are not induced (ϕ = 0). [ABSTRACT FROM AUTHOR]

Thermodynamical attributes of non-Newtonian fluids over stretched surfaces have gained pervasive essence due to extensive utilization in extruding plastic sheet procedures, liquid film condensation, glass blowing, paper production, biopolymer cylinder coatings, and so forth. So, currently communication is aimed to candidly explicate flow characteristic of Prandtl fluid generated by axial stretching of cylindrical surface. Mathematical modelling by using conservation laws of momentum, energy and concentration fields containing the aspects of magnetic field, convective heating, and chemical reaction are presented initially in the form of partial differential expressions. Later on, these attained PDEs are transmuted into nonlinear ordinary differential equations with implementation of similarity variables. Numerical approach renowned as shooting technique with improved coefficient of the Runge–Kutta (R–K) method by Cash and Karp is used to access accurate solution. Linear curved fitting analysis is also performed to analyze results. Influence of flow-controlling parameters on associated profiles is revealed through graphical visualization. Stream line plots representing flow behavior of Prandtl fluid versus different magnitudes of the curvature parameter are adorned. Variation in friction drag force at wall, heat flux, and concentration gradient are evaluated through numerical data and with interpolation of linear curved fittings. It is deduced from results that increasing curvature parameter momentum and temperature distributions enriches whereas skin-friction coefficient depicts reverse pattern. It is also inferred that temperature shows incrementing deviation in the absence of chemical reaction whereas concentration profiles exhibit reduction with consideration of influence of chemical reaction parameter. Magnetic field tends to reduce the velocity and create thinness of boundary layer thickness. [ABSTRACT FROM AUTHOR]

This work aims to interpret the heat and mass transmission of Sutterby fluid by exploring the effects of a magnetic field. Flow field equations in cylindrical coordinates are obtained by incorporating Darcy resistance law. Afterwards, a mathematical structure for the physical problem is formulated. This formulation yields an intricate nonlinear set of partial differential expressions. A suitable scaling group of variables is employed on subsequent equations to convert them into non-dimensional form. Dynamical and optimal analyses are performed to achieve physical features of the present problem from the solution. A graphical depiction is presented for the flow behavior of convoluted physical parameters on velocity, temperature, and concentration profiles. Additionally, the quantities (local shear stress coefficient, thermal convective transfer coefficient, and local mass flux coefficient in the limiting case) that are responsible for extracting the physical phenomena in the vicinity of a stretched surface are computed and demarcated by varying controlling flow parameters. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to highlight the studies of momentum and transmission of heat on mixed convection boundary layer Darcy‒Forchheimer flow of Casson liquid over a linear extending surface in a porous medium. The belongings of homogeneous‒heterogeneous retorts are also affianced. The mechanism of heat transmission is braced out in the form of Cattaneo‒Christov heat flux. Appropriate restorations are smeared to revolutionize coupled nonlinear partial differential equations conforming to momentum, energy and concentration of homogeneous‒heterogeneous reaction equations into coupled nonlinear ordinary differential equations (ODEs). Design/methodology/approach: Numerical elucidations of the transmogrified ODEs are accomplished via a dexterous and trustworthy scheme, namely optimal homotopy analysis method. The convergence of planned scheme is exposed with the support of error table. Findings: The exploration of mixed convection Darcy‒Forchheimer MHD boundary layer flow of incompressible Casson fluid by the linear stretched surface with Cattaneo‒Christov heat flux model and homogeneous‒heterogeneous reactions is checked in this research. Imitations of the core subsidized flow parameters on velocity, temperature and concentration of homogeneous‒heterogeneous reactions solutions are conscripted. From the recent deliberation, remarkable annotations are as follows: non-dimensional velocities in xa− and xb− directions shrink, whereas the non-dimensional temperature upsurges when the Casson fluid parameter ameliorates. Similar impact of Casson fluid parameter, magnetic parameter, mixed convection parameter, inertia parameter, and porosity parameter is observed for both the components of velocity field. An escalation in magnetic parameter shows the opposite attitude of temperature field as compared with velocity profile. Similar bearing of Casson fluid parameter is observed for both temperature and velocity fields. Enhancement in concentration rate is observed for growing values of (Ns) and (Sc), and it reduces for (k1). Both temperature and concentration of homogeneous‒heterogeneous upturn by mounting the magnetic parameter. Demeanor of magnetic parameter, Casson fluid parameter, heat generation parameter is opposite to that of Prandtl number and thermal relaxation parameter on temperature profile. Practical implications: In many industrial and engineering applications, the current exploration is utilized for the transport of heat and mass in any system. Originality/value: As far as novelty of this work is concerned this is an innovative study and such analysis has not been considered so far. [ABSTRACT FROM AUTHOR]

The present work concerns the momentum and heat transmission of the electro-magnetohydrodynamic (E-MHD) boundary layer Darcy-Forchheimer flow of a Sutterby fluid over a linear stretching sheet with slip. The nonlinear equations for the proposed model are analyzed numerically. Suitable techniques are used to transform the coupled nonlinear partial differential equations (PDEs) conforming to the forced balance law, energy, and concentration equations into a nonlinear coupled system of ordinary differential equations (ODEs). Numerical solutions of the transformed nonlinear system are obtained using a shooting method, improved by the Cash and Carp coefficients. The influence of important physical variables on the velocity, the temperature, the heat flux coefficient, and the skin-friction coefficient is verified and analyzed through graphs and tables. From the comprehensive analysis of the present work, it is concluded that by intensifying the magnitude of the Hartmann number, the momentum distribution decays, whereas the thermal profile of fluid increases. Furthermore, it is also shown that by aug- menting the values of the momentum slip parameter, the velocity profile diminishes. It is found that the Sutterby fluid model shows shear thickening and shear thinning behaviors. The momentum profile shows that the magnitude of velocity for the shear thickening case is dominant as compared with the shear thinning case. It is also demonstrated that the Sutterby fluid model reduces to a Newtonian model by fixing the fluid parameter to zero. In view of the limiting case, it is established that the surface drag in the case of the Sutterby model shows a trifling pattern as compared with the classical case. [ABSTRACT FROM AUTHOR]

Two-dimensional flow of Casson fluid toward an exponentially stretched surface in view of Cattaneo-Christove flux theory is discoursed in current communication. Flow pattern within boundary layer under the effectiveness of magnetic field is also contemplated in the communication. Non-dimensionalized governing expressions are attained through transformation procedure. To anticipate the fascinating features of present work, solution of resulted nonlinear differential system is computed with the collaborated help of shooting scheme and Runge-Kutta method. The influence of involved variables on velocity and temperature fields is scrutinized. Contribution of thermal relaxation is explicitly pointed out. Evaluation of convective heat transfer and friction factor in the fluid flow is visualized through graphs and tables. Additionally, the assurance of present work is affirmed by developing comparison with previous findings in the literature which sets a trade mark for the implementation of numerical approach. It is inferred from the thorough examination of the analysis that present formulation reduces to classical Fourier’s problem by considering Λ=0. Furthermore, decreasing pattern in temperature distribution is depicted in the presence of Cattaneo-Christove flux law as compared to heat transfer due to the Fourier’s law. [ABSTRACT FROM AUTHOR]

Present study is addressed to express the implementation of Keller-Box technique on physical problem in the field of fluid rheology, for this purpose the Williamson fluid flow is considered along a cylindrical stretching surface manifested with temperature stratification. The flow model is translated mathematically in terms of differential equations. Numerical simulation is executed to trace out the solution structure of developed differential system. The graphical outcomes for the flow regime of two different geometries (i-e cylindrical and plane surface) are reported and examined towards involved physical parameters. Furthermore, the local skin friction coefficient and local Nusselt number are computed numerically. A remarkable agreement of present study is noticed with the previously published results, which confirms the implementation and validation of Keller-Box scheme and it will serve as a helping source for the future correspondence. [ABSTRACT FROM AUTHOR]

An attempt has been constructed in the communication to envision heat and mass transfer characteristics of viscous fluid over a vertically rotating cone. Thermal transport in the fluid flow is anticipated in the presence of viscous dissipation. Whereas, concentration of fluid particles is contemplated by incorporating the diffusion-thermo (Dufour) and thermo-diffusion (Soret) effects. The governing equations for concerning problem is first modelled and then nondimensionalized by implementing compatible transformations. The utilization of these transformations yields ordinary differential system which is computed analytically through homotopic procedure. Impact of velocity, temperature and concentration profiles are presented through fascinating graphics. The influence of various pertinent parameters on skin friction coefficient, Nusselt number and Sherwood number are interpreted through graphical and tabular display. After comprehensive examination of analysis, it is concluded that temperature of fluid deescalates for growing values of Soret parameter whereas it shows inciting attitude towards Dufour parameter and similar agreement is observed for the behavior of concentration profile with respect to these parameters. Furthermore, the affirmation of present work is established by developing comparison with previously published literature. An excellent agreement is found which shows the credibility and assurance of present analysis. [ABSTRACT FROM AUTHOR]

In present analysis boundary layer flow of Sisko fluid over stretching cylinder is analyzed. Combined effects of variable thermal conductivity and viscous dissipation are assumed in heat transfer. The modeled boundary layer partial differential equations are transfigured into ordinary differential equations by using suitable transformations. These nonlinear ordinary differential equations are solved numerically by Runge-Kutta-Fehlberg method. The accuracy of computed results is certified by comparing with existing literature. To interpret the effects of flow parameters on velocity and temperature profiles graphs are developed. The influence of all physical parameters on skin friction coefficient and local Nusselt number are discussed via tabular and graphical form. [ABSTRACT FROM AUTHOR]

Current analysis illustrates the systematic survey about the flow features imparted by viscous fluid between two coaxially rotated disks embedded in a permeable medium. Energy equation has been built by encompassing Cattaneo–Christov heat flux law.Prevailing non-linear PDEs are converted into non-linear ODEs by utilizing Von Karman transformations. Afterwards, the attained differential system is solved by capitalizing implicit finite difference scheme. Interpretation regarding the impact of dimensionless involved parameters on axial, tangential and radial components of velocity, thermal distribution is exhibited. Comparison for skin friction coefficients on walls of disks is also manifested. An excellent agreement with previous work is established which assures the reliance of present work. After getting through intellect about the variations it is disclosed that the magnitude of axial and radial velocities diminishes at lower disk contrary to upper disk for intensifying magnitude of Reynold number. Furthermore, the shear stress rate at walls of upper and lower disks is also deliberated. Increment in tangential component of velocity is also manifested for uplifts values of Reynold number. In case of thermal distribution, it is deduced that thermal field decrements for increasing of Pr and thermal relaxation parameter. It is worthy to mention that shear drag coefficient at wall of lower disk decreases conversely to the wall shear coefficient magnitude at wall of upper disk. • The skin friction coefficient at both disks is less for greater value of rotational parameter. • At the lower disk, the radial and axial velocity profile increases for maximum value of A 1. • Thermal effects are reduced for both thermal relaxation and Prandtl number. • For rotational and stretching parameters, the tangential velocity profile increases at disk. [ABSTRACT FROM AUTHOR]