Purpose-The purpose of this paper is to study numerically the influence of a magnetic field on the transient free convective boundary layer flow of a nanofluid over a moving semi-infinite vertical cylinder with heat transfer Design/methodology/approach-The problem is governed by the coupled non-linear partial differential equations with appropriate boundary conditions. The fluid is a water-based nanofluid containing nanoparticles of copper. The Brinkman model for dynamic viscosity and Maxwell-Garnett model for thermal conductivity are used. The governing boundary layer equations are written according to The Tiwari-Das nanofluid model. A robust, well-tested, implicit finite difference method of Crank-Nicolson type, which is unconditionally stable and convergent, is used to find the numerical solutions of the problem. The velocity and temperature profiles are studied for significant physical parameters such as the magnetic parameter, nanoparticles volume fraction and the thermal Grashof number Gr. The local skin-friction coefficient and the Nusselt number are also analysed and presented graphically. Findings-The present computations have shown that an increase in the values of either magnetic parameter M or nanoparticle volume fraction decreases the local skin-friction coefficient, whereas the opposite effect is observed for thermal Grashof number Gr. The local Nusselt number increases with a rise in Gr and f values. But an increase in M reduces the local Nusselt number. Originality/value-This paper is relatively original and presents numerical investigation of transient two-dimensional laminar boundary layer free convective flow of a nanofluid over a moving semi-infinite vertical cylinder in the presence of an applied magnetic field. The present study is of immediate application to all those processes which are highly affected by heat enhancement concept and a Free convective flow 1393

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In the present study, the effects of chemical reaction on unsteady free convection flow of a viscous, electrically conducting, and incompressible fluid past a moving semi-infinite vertical cylinder with mass transfer and temperature oscillation is studied. The dimensionless governing partial differential equations are solved using an implicit finite-difference method of Crank-Nicolson type, which is stable and convergent. The transient velocity, transient temperature, and transient concentration profiles are studied for various parameters. The local as well as average skin-friction, Nusselt number, and Sherwood number are also analyzed and presented graphically. The results are compared with available computations in the literature, and are found to be in good agreement.

The present study intends to explore heat transfer characteristics of the unsteady natural convective flow of Cu–Al2O3/water hybrid nanofluid due to exponentially accelerated vertical plate. 2D Laminar viscous incompressible boundary layer fluid flow is considered in the presence of MHD and accelerating parameter. The governing partial differential equations with appropriate boundary conditions are solved using the Crank-Nicolson numerical technique. Plots for skin friction coefficient, velocity, temperature, Nusselt number concerning Magnetic parameter (M), Accelerating parameter (a), Grashof number (Gr), Volume fraction (Φ2), and time are disclosed. The study imparted that Cu–Al2O3 hybrid nanoparticles with water as base fluid facilitate a higher heat transfer rate and soaring Nusselt number compared to nanofluid Cu/water. Furthermore, we found an elevated skin friction coefficient in nanofluid Cu/water than in hybrid nanofluid Cu–Al2O3/water in all non-dimensional parameters.