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A numerical investigation has been done to study the impact of nonlinear magnetic field, nonlinear thermal radiation, variable thickness, and Brownian motion on flow and heat transfer characteristics (i.e., skin friction and surface heat flux) as a physical application. Moreover, the impact of these forces on the rate of cooling and the mechanical properties (i.e., hardness, ductility, ...) of a surface that is cooled using nanofluid as a coolant is explored. The governing boundary layer equations describing the problem are transformed to ordinary differential equations using the similarity transformation method and are then solved numerically using the fourth-order Runge-Kutta method with shooting technique with the assistance of Mathematica program. Key words: nanofluids, variable thickness, nonlinear thermal radiation, magnetic field. Nous presentons une etude numerique de l'impact d'un champ magnetique non lineaire, de la radiation thermique non lineaire, de l'epaisseur variable et du mouvement brownien sur les caracteristiques d'ecoulement et de transfert de chaleur (i.e. le frottement superficiel et le flux de chaleur de surface) en tant que un systeme physique. Nous etudions aussi l'impact de ces forces sur le taux de refroidissement et les proprietes mecaniques (i.e., la durete, la ductilite, ...) des surfaces refroidies en utilisant un nanofluide comme refroidisseur. Les equations directrices de la couche limite sont transformees en en equations differentielles ordinaires par la methode des transformations de similarite, qui sont ensuite solutionnees par methode de Runge-Kutta du quatrieme ordre avec une technique de tir en utilisant un programme de Mathematica. [Traduit par la Redaction] Mots-cles: nanofluide, epaisseur variable, radiation thermique non lineaire, champ magnetique., 1. Introduction Study of boundary layer behavior over a moving surface is an important problem because of its importance to industry processes, such as paper production, plastic extrusion, and fibers. [...]

The effect of variable thermal conductivity on the characteristics of heat transfer and mechanical properties of a moving surface on a Casson nanofluid flow as a coolant has been studied in this paper. We used similarity transformation method to transform the equations of the governing boundary-layer into ODE which are solved numerically using a mix of fourth order Runge-Kutta method and find root technique. Different values relevant parameters have been studied on the features of velocity, temperature, and the profiles of concentration and discussed in details for different values of various parameter as shape parameter, heat source parameter, radiation parameter, and magnetic parameter. The results were compared with previous published researches and obtained it in a good agreement and the results were tabulated. Furthermore, Nusselt number, Sherwood number, and the skin friction values with different parameters were calculated and the influence of theses physical quantities on the mechanical properties on the surface are analyzed and discussed in details. [ABSTRACT FROM AUTHOR]

The present work provides an analysis of the hydromagnetic nanofluid boundary-layer flow over a rotating disk in a porous medium with a constant velocity in the presence of hall current and thermal radiation. The governing PDE system that describes the problem is converted to a system of ODE by the similarity transformation method, which solved analytically using optimal homotopy asymptotic method. The velocity profiles and temperature profiles of the boundary-layer are plotted and investigated in details. Moreover, the surface skin friction, rate of heat transfer are deduced and explained in details. [ABSTRACT FROM AUTHOR]

The effect of thermal radiation, heat generation, suction/injection, nanoparticles type, and nanoparticle volume fraction on heat transfer characteristics and the mechanical properties of unsteady moving cylinder embedded into cooling medium consist of water with Cu, Ag, or Al2O3 particles are studied. The governing time dependent boundary layer equations are transformed to ordinary differential equations containing unsteadiness parameter, thermal radiation parameter, heat source parameter, suction/injection parameter, curvature parameter, nanoparticle volume fraction, and Prandtl number. These equations are solved numerically. The velocity and temperature profiles within the boundary layer are plotted and discussed in details for various values of the different parameters. Also the effects of the cooling medium and the external thermal forces on the mechanical properties of the cylinder are investigated. [ABSTRACT FROM AUTHOR]