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This study presents a numerical investigation on the magnetohydrodynamic (MHD) stagnation point flow of a ferrofluid with Newtonian heating. The black oxide of iron, magnetite (Fe3O4) which acts as magnetic materials and water as a base fluid are considered. The two dimensional stagnation point flow of cold ferrofluid against a hot wall under the influence of the uniform magnetic field of strength is located some distance behind the stagnation point. The effect of magnetic and volume fraction on the velocity and temperature boundary layer profiles are obtained through the formulated governing equations. The governing equations which are in the form of dimensional non-linear partial differential equations are reduced to dimensionless non-linear ordinary differential equations by using appropriate similarity transformation. Then, they are solved numerically by using the Keller-box method which is programmed in the Matlab software. It is found that the cold fluid moves towards the magnetic source that is close to the hot wall. Hence, leads to the better cooling rate and enhances the heat transfer rate. Meanwhile, an increase of the magnetite nanoparticles volume fraction, increases the ferrofluid capabilities in thermal conductivity and consequently enhances the heat transfer.

Mixed convection of unsteady non-coaxial rotation flow of viscous fluid over an accelerated vertical disk is investigated. The motion in the fluid is induced due to the rotating and buoyancy force effects. The problem is formulated and extended in terms of coupled partial differential equations with some physical boundary and initial conditions. The non-dimensional equations of the problem are obtained by using the suitable non-dimensional variables. The exact solutions of non-coaxial velocity and temperature profiles are obtained by using Laplace transform method which are satisfying all the initial and boundary conditions. The physical significance of the mathematical results is shown in various plots and is discussed for Grashof and Prandtl numbers as well as magnetic, porosity and accelerated parameters. It is found that, the velocity with the effect of acceleration is higher compared to constant velocity. In limiting sense, the present solutions are found identical with published results.

In this paper MHD flow of Casson hybrid nanofluids are investigated with Caputo time-fractional derivative. Alumina (Al) and copper (Cu) are used as nanoparticles in this study with heat, mass transfer and MHD flow over a vertical channel in a porous medium. The problem is modeled using Caputo fractional derivatives and thermophysical properties of hybrid nanoparticles. The influence of concerned parameters is investigated physically and graphically on the heat, concentration and flow. The effect of volume fraction on thermal conductivity of hybrid nanofluids is observed.

In this paper, the effects of heat and mass transfer (double convection) on unsteady magnetohydrodynamic flow of incompressible viscous fluids in a porous medium under the influence of non-coaxial rotation are analyzed. The flow is induced due to buoyancy force and oscillating bounding disk. The dimensionless governing equations for the velocity field, temperature and concentration distributions are solved analytically by using the Laplace transform technique. The results for skin friction, Nusselt number and Sherwood number are also presented. The numerical results are computed for the effects of various indispensable flow parameters and displayed using several graphs. The numerical results showed the behavior of the physical parameters on the fluid flow in primary and secondary velocities as well as on heat and mass transfer. It is found that the velocity profiles for solution that considering heat and mass transfer are higher compared to solution without mass transfer. Physically, mass is a particle that transfers heat energy from one place to another place and enhances the velocity to increase. It is worth mentioning that the analytical solutions are in excellent agreement with the numerical solutions obtained by Gaver–Stehfest algorithm and present solutions are found identical with the published results.