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This paper presents an application of the Boundary Element Method (BEM) in engineering to numerically analyse the thermal behaviour of structures executed by layers that present different temperatures at the time of overlapping and/or that present some type of internal heat generation. This type of phenomenon occurs, for example, in large concrete structures, where the structure has its temperature altered due to the hydration reaction of the cement during the concrete curing process. Using the developed formulation, it is possible to simulate the temperature field at all stages of the construction process and in different situations by changing the thermophysical parameters, taking into account the thermal influence of one layer on the others and on the structure as a whole. With the simulation results, it is also possible to define the deposition time between the layers of the structure, which is important information for cases in which the temperature variation may imply the appearance of thermal stresses, for example, or when the maximum temperature reached do not exceed a certain limit. The cases presented were directed to concrete structures, mainly roller-compacted concrete (RCC) dams, whose details of the construction process, as well as the heat diffusion process during the concrete curing process and the entire formulation of the boundary element, are presented below. [ABSTRACT FROM AUTHOR]

Purpose: The current investigation is communicated to analyze the characteristics of squeezed second grade nanofluid flow enclosed by infinite channel in the existence of both heat generation and variable viscosity. The leading non-linear energy and momentum PDEs are converted into non-linear ODEs by using suitable analogous approach. Design/methodology/approach: Then the acquired non-linear problem is numerically calculated by using Bvp4c (built in) technique in MATLAB. Findings: The influence of certain appropriate physical parameters, namely, squeezed number, fluid parameter, Brownian motion, heat generation, thermophoresis parameter, Prandtl number, Schmidt number and variable viscosity parameter on temperature, velocity and concentration distributions are studied and deliberated in detail. Numerical calculations of Sherwood number, Nusselt number and skin friction for distinct estimations of appearing parameters are analyzed through graphs and tables. It is examined that for large values of squeezing parameter, the velocity profile increases, whereas opposite behavior is noticed for large values of variable viscosity and fluid parameter. Moreover, temperature profile increases for large values of Brownian motion, thermophoresis parameter and squeezed parameter and decreases by increases Prandtl number and heat generation. Moreover, concentration profile increases for large values of Brownian motion parameter and decreases by increases thermophoresis parameter, squeezed parameter and Schmidt number. Originality/value: No one has ever taken infinite squeezed channel having second grade fluid model with variable viscosity and heat generation. [ABSTRACT FROM AUTHOR]

A common technique of enhancing thermal conducting is through the insertion of small magnetic particles or other nanoparticles with high thermal conductivity. In this research letter, manganese Zinc ferrite (MnZnFe 2 O 4) and Nickle Zinc ferrite (NiZnFe 2 O 4) were examined to assess the maximum possibility of enhancing thermal conductivity for current heat dissipation fluid problem. Therefore, a mathematical modeling is developed for steady, incompressible, 2D ferromagnetic hybrid (Manganese Zinc Ferrite, Nickle Zinc Ferrite) nanomaterial of micropolar fluid (non-Newtonian) towards moving surface of sheet. Darcy–Forchheimer porous medium effect is studied through momentum equation and thermal stratification effect is employed in heat equation. Micro-rotation and spin gradient effects are accounted. The model of heat diffusion initiated by Fourier law of heat conduction is implemented for energy transport assessment. The governing partial differential equations are altered through implementation of appropriate similarity variables into ordinary ones. Built-in-Shooting technique leads to the solutions of dimensionless flow equations. Behaviors of physical phenomenon are sketched by taking various positive estimations of concerning material constraints. The comparative solutions subject to manganese Zinc ferrite (MnZnFe 2 O 4) and Nickle Zinc ferrite (NiZnFe 2 O 4) hybrid nanofluids are presented and studied. From obtained results, we observed that velocity is more for MnZnFe 2 O 4 -NiZnFe 2 O 4 -C 8 H 18 as compared to MnZnFe 2 O 4 -NiZnFe 2 O 4 -C 10 H 22 -C 8 H 18 hybrid nanomaterials. [ABSTRACT FROM AUTHOR]

This article provides insight into the study of hydromagnetic flow of a chemically reacting water based nanofluid of Copper (Cu), Silver (Ag) and Ferrous Ferric Oxide (Fe 3 O 4) nanoparticles over a stretching permeable sheet with heat generation, nanoparticle volume fraction, Soret number, Eckert number and porosity. The governing system of PDEs is reduced to nonlinear ODEs by the tool of similarity transformations, and is solved by fourth order Runge–Kutta scheme with the shooting method via MATLAB. Output of the nanofluid velocity, temperature and concentration for the involved material parameters as well as the correlated engineering physical quantities like coefficient of skin friction and rate of heat transfer are demonstrated via single plots of three nanopartciles and Tables. Heat generation and Soret number for three different nanoparticles play a significant role throughout the investigation. Greater nanoparticle volume fraction decreases the liquid velocity, while a non-decline situation has occurred for liquid temperature. Furthermore, the velocity always overshoots for Fe 3 O 4 -water nanofluid, followed by Cu and Ag–water nanofluid, whereas the reverse performance is observed for the temperature profiles. An excellent validation of this model is accomplished. The adopted numerical scheme of RK-Shooting is stable and convergent in the same domain throughout the numerical calculations. The proposed investigation shows the importance of three nanoparticles in medical industry and biocompatibility engineering. Also, these nanoparticles can be used in physics, engineering, space technology, high temperature and cooling process, medicines, biosensors, paints, cosmetics, conductive coatings and medical devices. • Impact of Fe 3 O 4 , Cu and Ag for water based nanofluid in porous regime is studied. • 4th order RK-Shooting Technique have been employed to solve the non-linear PDE. • Significant impact has been observed due to various conductivity of the nanoparticles. • Importance of these nanoparticles can be found in medical industry & bio-engineering. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to discuss the salient aspects of the Darcy–Forchheimer flow of viscous liquid in carbon nanotubes (CNTs). CNTs are considered as nanofluid, and water is taken as the continuous phase liquid. The flow features are discussed via curved surface. Water is taken as the base liquid. Flow is generated via nonlinear stretching. Energy expression is modeled subject to heat generation/absorption. Furthermore, convective conditions are considered at the boundary. The Xue model is used in the mathematical modeling which describes the features of nanomaterials. Both types of CNTs are considered, i.e. single-walled CNTs and multi-walled CNTs. Design/methodology/approach: Appropriate transformations are used to convert the flow expressions into dimensionless differential equations. The bvp4c method is used for solution development. Findings: Velocity enhances via higher estimations of nanoparticles volume fraction while decays for higher Forchheimer number, curvature parameter, behavior index and porosity parameter. Furthermore, thermal field is an increasing function of nanoparticle volume fraction, behavior index, Forchheimer number and porosity parameter. Originality/value: Here, the authors have discussed two-dimensional CNTs-based nanomaterial Darcy–Forchheimer flow of viscous fluid over a curved surface. The authors believe that all the outcomes and numerical techniques are original and have not been published elsewhere. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to address the impact of induced magnetic field in mixed convective stagnation flow of TiO2-Cu-water hybrid nanofluid towards a stretchable sheet. Non-linear thermal radiation and heat source/sink are accounted. Flow of hybrid nanofluid is discussed. Non-linear partial differential expressions are converted to ordinary ones through appropriate transformations. Design/methodology/approach: The obtained systems are solved for convergence solutions via homotopy analysis method. Graphical results are discussed for different physical variables on the velocity, induced magnetic field and temperature fields for both Cu water nanofluid and TiO2-Cu-water hybrid nanofluid. Finally, the effect of different physical variables on skin friction coefficient (Cfx) and Nusselt number Nux in the presence of water nanofluid and TiO2-Cu-water hybrid nanofluid are discussed. Findings: Velocities and induced magnetic field are increasing functions of mixed convection parameter and nanoparticle volume fraction. Temperature rises for higher radiation parameter. Skin friction is greater in case of Cu-water nanoliquid, while Nusselt number is less for Cu-water nanofluid when they are compared with hybrid nanoliquid TiO2-Cu-water. Originality/value: No such work is not yet present in the literature. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to elaborate the characteristics of magneto-Maxwell nanoliquid toward moving radiated surface. Flow analysis subject to Darcy–Forchheimer concept is studied. Newtonian heat/mass conditions and heat source aspects are taken into account for modeling. Apposite transformations are introduced for non-dimensionalization process. Design/methodology/approach: Optimal homotopy analysis method is implemented to compute convergent solutions of nonlinear ordinary differential equations. Findings: Temperature field increments when thermophoresis, heat generation and Brownian movement parameters are increased, whereas reverse situation is noticed for larger Prandtl number. The results also witness that concentration distribution has opposite characteristics for larger thermophoresis and Brownian movement parameters. Furthermore, the presented analysis reduces to traditional Darcy relation in the absence of local inertia coefficient. Originality/value: As per the authors' knowledge, no such analysis has been yet reported. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to introduce the concept of improved Fourier–Fick laws subjected to variable fluid characteristics. Flow analysis in the stagnation region of Oldroyd-B fluid is elaborated. Heat generation is present. Design/methodology/approach: Optimal homotopy analysis method is used to obtain convergent solutions. Findings: The outcomes reveal reduction in penetration depths of temperature and concentration due to involvement of thermal and solutal relaxation times of fluxes. Originality/value: As per the authors' knowledge, such analysis has not yet been reported. [ABSTRACT FROM AUTHOR]

Purpose – In this study, the purpose was to introduce two-dimensional hyperbolic heat conduction equations in order to simulate the fast precooling process of a cylindrically shaped food product with internal heat generation. A modified model for internal heat generation due to respiration in the food product was proposed to take the effect of relaxation time into account. The obtained governing equations were solved numerically using an efficient finite difference technique. The influence of Biot number and heat generation parameters on thermal characteristics was examined and discussed. The results based on hyperbolic model were compared with the classical parabolic heat diffusion model. The present numerical code was validated via comparison with analytical solution and a good agreement was found. Design/methodology/approach – The obtained governing equations were solved numerically using an efficient finite difference technique. Findings – The influence of Biot number and heat generation parameters on thermal characteristics was examined and discussed. The results based on hyperbolic model were compared with the classical parabolic heat diffusion model. The present numerical code was validated via comparison with analytical solution and a good agreement was found. Originality/value – Two-dimensional analysis of fast precooling of cylindrical food product based on hyperbolic heat conduction model has not been investigated yet. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this work is to study heat and mass transfer from mixed convection flow of polar fluid along a plate in porous media with chemical reaction. Design/methodology/approach – The governing equations for this problem are solved numerically. Findings – Polar fluids behave very differently from Newtonian fluids. Originality/value – This work is original as little work has been reported for polar fluids. [ABSTRACT FROM AUTHOR]

Abstract: Natural convection laminar boundary layer flow from a horizontal circular cylinder with a uniform surface temperature at presence of heat generation has been investigated. The governing boundary layer equations are transformed into a non-dimensional form and the resulting nonlinear systems of partial differential equations are solved numerically applying two distinct methods namely (i) implicit finite difference method together with the Keller box scheme and (ii) series solution technique. The results of the surface shear stress in terms of the local skin friction and the surface rate of heat transfer in terms of the local Nusselt number for a selection of the heat generation parameter γ (=0.0,0.2,0.5,0.8,1.0) are obtained and presented in both tabular and graphical formats. Without effect of the internal heat generation inside the fluid domain for which we take γ =0.0, the present numerical results show an excellent agreement with those of Merkin [J.H. Merkin, Free convection boundary layer on an isothermal horizontal circular cylinders, in: ASME/AIChE, Heat Transfer Conference, St. Louis, MO, August 9–11, 1976]. The effects of γ on the fluid velocity, temperature distribution, streamlines and isotherms are examined. [Copyright &y& Elsevier]

• Uplifting in ϕ 2 near the boundary causes to dwindle f ′(ξ) and enhance it in long distance from boundary. • Velocity field g (ξ) enhances with the enhancing ∈ and dwindles with increasing the Ha, We and ϕ 2. • The values of thermal Biot number is increased, the θ (ξ)profile also enhanced. • Surface drag force in terms of Ha changes has inverse relation to x -axis and directly relation to y -axis. • Rate of heat transfer is more in M o S 2 − A g hybrid nanofluid is more than that of T i O 2 − C u O hybrid nanofluid. Herein, the numerical investigation is carried out to study the flow and heat transfer analysis through a hybrid nanofluid flow over a porous medium. The governing partial differential equations are transformed into ordinary differential equations with the help of similarity transformations. The resulting ODEs are solved by a numerical technique using RKF-45 Method. Through graphs, the impacts of pertinent parameters on energy and velocity field were deliberated. Indeed, the outcomes were quite promising. It is noticed that, the surface drag force in terms of Hartman number changes has inverse relation to x -axis and directly relation to y -axis. Furthermore, the rate of heat transfer is more in MoS_2-Ag hybrid nanofluid is more than that of TiO_2-CuO hybrid nanofluid. [ABSTRACT FROM AUTHOR]